US2272494A - Safety device - Google Patents

Description

Feb. l0, 1942. P. wmsLow SAFETY DEVICE 2 Sheets-Sheet 1 Filed March 1, 1941 LAWRENCE P. WIN s LOW Enventor G ttorncgs Patented Feb. 10, 1942 SAFETY DEVICE Lawrence P. Winslow, Berkeley, Calif.; dedicated to the free use of the People in the territor of the United States Application March 1, 1941, Serial No. 381,276

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 1 Claim.

This invention relates to a mechanical safety 2 device for use in connection with a supporting rope or other cable, and the general object is the provision of such a device which can be attached to a carrier, such as an elevator carriage or platform or to the harness or belt of a person suspended from a vertical cable, such as a rope, such that the device normally clamps the cable and holds the carrier at a fixed position along the cable, means being provided for unclamping the cable when it is desired to change position, reclamping of the cable being accomplished automatically so that should the operator lose control from any cause whatsoever during the change of position, such as from accidental causes or illness, the device instantly checks the fall of the carrier along the cable to prevent injury.

This invention is particularly useful to persons engaged in such occupations as window cleaning, house painting, building construction, mountain climbing, repairing of overhead telephone lines and the like.

Further objects and advantages of this invention will be apparent from the following description and the accompanying drawings, in which drawings:

Figure 1 is a view showing an embodiment of my invention attached to an elevator carriage suspended from a rope on the side of the build- 11%? Figure 2 is a front elevational view of the device detached from the carriage, partly in section; and

Figure 3 is a side elevational view.

Referring with more particularity to the drawings, in which like numerals designate like parts, the embodiment illustrated comprises a pair of plates I and II held in spaced relation by means of tubular spacers I2 and rivets I3. Between the plates I0 and II there is secured on one side abutment blocks I4, I4 of any suitable number, preferably two, as illustrated. The inner sides I5 of the abutment blocks are corrugated to provide a gripping surface. Opposite each abutment block there is pivotally mounted on a shaft I8 a rocker dog I6 having a corrugated or gripping surface I! in the general shape of a spiral facing its corresponding abutment block I4, so

as to vary the distance between its corrugated surface I! and the surface I5 of its corresponding abutment block. To provide simultaneous action of the dogs I6 when more than one is employed, a bar I 9 is pivotally connected to arms 20 of the dogs, which arms extend beyond plates I0 and II, substantially as illustrated. In operation a cable 2I is threaded between the plates I0 and I I and between the abutments I4 and the dogs I6. To hold the dogs I6 in operative position against the cable 2I, a spring 22 is compressibly mounted between the toe 23 of each do and a suitable abutment 24 fixed to the plates I 0 and I I, substantially as illustrated. With the dogs I6 contacting the surface of the cable 2|, an upward pull on the rope would tend to cause the dogs I6 to turn so as to grip tighter the cable between the surface I! and the abutment block I4. Consequently, when the cable is used for supporting an elevator carrier, such as the carriage 21, as illustrated in Figure 1, the upper end of the cable is fixed to the building 26 while the carriage 21 is attached to the plates I0 and II by any suitable means, such as clevises 28 disposed through suitable apertures 29 through the plates I0 and II. When the operator desires to change to a lower position, the dogs I6 are turned against the action of the springs 22 by pressing on the bar I9, thereby releasing the grip on the cable 2|, whence the position of the carriage can be changed along the cable. If, for any reason, during such a change of position, the operator should lose control, release of the bar I9 would automatically cause the springs 22 to reset the dogs I6 against the cable 2I and the movement of the carriage would be arrested. When it is desired to change to a higher elevation, it is not necessary for the operator to operate the bar I9, since movement of the device upward on the cable would automatically cause the dogs to turn about their pivots and release the grip on the cable.

Having thus described my invention, I claim:

A device of the character described comprising a pair of plates secured together in spaced relation, fixed abutments between said plates, spirallike abutments, one for each fixed abutment. pivoted between said plates facing said fixed abutments so that movement of said spiral-like abutments about their pivots causes the distance between them and their corresponding fixed abutments to change, said spiral-like abutments having lever arms, a bar pivoted to said arms so as to constrain said pivoted abutments to operate simultaneously, and means between said plates, including a spring, for urging said spiral-like abutments to turn about their pivots in the direction opposite to the direction of evolution of their spirals.

LAWRENCE P. WINSLOW.

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