US2550764A - Safety device for hoists or lifts - Google Patents

Description

May 1, 1951 c. J. BRISTOL SAFETY DEVICE FOR HOISTS OR LIFTS Filed July 11 1945 1N VEN TOR. J Brwfal,

Patented May 1, 1951 SAFETY DEVICE FOR HOISTS OR LIFTS Cyrus J. Bristol, Des Moines, Iowa, assignor to The Wayne Pump Company, Fort Wayne, Ind., a corporation of Maryland Application July 11, 1945, Serial No. 604,407

6 Claims. (01. 254493) This invention pertains to elevators or lifts.

It is an object of this invention to provide a new and improved safety device for hoists or lifts.

Another object of the invention is to provide a safety leg for hoist which moves to inoperative position. as the hoist lowers, after having been tmoved a predetermined distance from safety posi- Another object of the invention is to provide a safety device for a hoist or lift, which device is installed wholly above ground and prevents rotainstalled as when the hoist or lift is being installed.

Another object of the invention is to provide a safety device for a hoist or lift which is so constructed and arranged that the safety member never touches the floor (or ground) while the hoist or lift is being moved to raised or lowered positions. Another object of the invention is to provide a safety and non-rotating device for a hoist so constructed and arranged that the device is adapted to be moved through a relatively small angle to condition it for hoist lowering operation.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings, which illustrate embodiments of the device and wherein like reference characters are used to designate like parts- Figure 1 is a fragmentary side elevation of a form of safety mechanism embodying the invention, the view showing the same in various positions of operation; and V Figure 2 is a fragmentary top plan view of the safety mechanism illustrated in Figure 1.

As shown in the drawings a movable safety leg is provided to hold a hoist structure in its ele vated position.

In order to safeguard the operator from accidental descent of the lift from raised position, a safety leg is provided which is automatically raised to operative position when the lift is raised. The upper end of the safety leg is connected to the bracket IIB which is shown as secured to the bracket I55 on the hoist superstructure I62. A safety leg may be either a single member such as the tube H2 or may be a frame structure. The

operation, of course, would be the same in either case, and only the single tube structure is described. The tube IIZ is pivoted as at I'M to the spaced arms "'5 and I18 of bracket I79, and tube H2 is provided with the bracket I pivoted as at I 82 to the rod I B l which is slidably received or telescopes into the pipe I86. Said pipe I 86 is provided with the legs I83, braced at I90 and pivoted as at I92 to the lugs I94 of bracket I96 provided on the floor or ground, pivot I92 being preferably in vertical alignment with the pivot I82 when the safety leg is in operative or full line position II2d as illustrated in Figure 1. When the assembly I88, I84, I86, I88, I96 is used the hoist cannot be rotated about its vertical axis.

Tube I12 is provided with the locking pin or member I98 adapted to engage within the slot 200 of the locking or latch member 202, member 292 being fixedly mounted to the shaft 2M journaled at one end in arm I18 of bracket I19, and journaled in lug 205 also provided on bracket I10, the shaft being provided with the operating handle or lever 208 which may be disposed within the rails or outside of the adjacent rail of the superstructure. The slot 209 is provided with the locking shoulder Zlt adapted to receive the pin I98 to lock the tube I12 in position II'Zc for permitting lowering of the lift and rendering the safety leg inoperative during the lowering operation.

When the hoist is raised from its lowered position the safety leg will move from inoperative position where it is horizontal, as at I'IZa (Figure l) to the full operative position as shown at "M, and in this case the pin I98 will have moved past the shoulder 2H1 into the elongated recess 290a. In so moving pin I98 will not engage shoulder ZII] because due to the weight of lever 208 and member 282 the pin will travel along the top edge of its slot to the full line position shown in Figure 1 wherein the safety leg is vertical. When it is desired to lower the lift, the lever 208 must first of all be moved in a counter-clockwise direction (Figure 6) to the latched or dotted line position as shown at 208a where the pin I98 will engage the shoulder 2H1. permitted, due to the telescopic connection between the rod I84 and pipe I86. When the operation of the hoist or lift is reversed and the superstructure moves downwardly it will be seen that pivot I14 moves vertically downwardly as does pivot I82 until rod IBt has telescoped into tube I86, at which time pivot I82 will pivot around pivot I92 preventing the end of leg I12 from touching the ground, and causing it to move This movement will be through positions H20 and I122), until finally it is in position Il2a, at which time the superstructure is in its lowermost position. Up until the time that rod I84 has telescoped into tube I88, the pin I98 has been in latched position, that is, in engagement with shoulder 210. After rod 184 has been received in tube I86 and as the lift descends moving the leg from I'l -2b toward 112a, the latch becomes unlatched as the telescoped rod I84 and tube N36 cause pin I98 to move from shoulder 210 into engagement with the top edge of slot 200.

It is to be understood that this application is not to be limited by the exact embodiments of the device shown, which are merely by way of member inoperative when the hoist is being.

raised but being movable to move the rigidmem- #ber from operative position to .an intermediate position, :a telescopic member pivoted :at one end :to the rigid member and at the other end to a point fixed with respect to the superstructure, said telescopic member collapsing a predeter- .-mined amount as the hoist is -loweredand thereafter moving the rigid member :to inoperative position 'as the hoist is lowered to -a position substantially parallel to the superstructure.

'2. In a hoist, the combination of :a superstructure, means for raising and lowering said superstructure, sa'fet-y mechanism movable from an inoperative position to an operative position when said superstructure is raised, :said safety mechanism comprising a rigid member pivoted adjacent the upper end thereof to the hoist, a latch member inoperative when the hoist is being raised but being movable to move theirigidmemher from operative position to an intermediate .position, a telescopic member pivoted at .one end to the rigid member and at the other end to a point fixed with respect to the superstructure, said telescopic member collapsing -a predetermined amount as the hoist is lowered and thereafter releasing said latch and moving the rigid member to inoperative position as .the hoist is lowered .to .a position substantially parallel to the superstructure.

'3. .In a hoist, the combination of a superstructure,.means for raising and lowering said superstructure, said means having a portion fixed .as in the ground, safety mechanism interposed between .saidsuperstructure and the groundmovableirom an inoperative position to an operative position when said superstructure is raised, said safety mechanism comprising a rigid member pivoted adjacent the upper end thereof to said hoist, a latch member pivoted tosaid hoist adjacent the pivot of said rigid member, a locking member on said rigid member, said latch member having a part movable with .said latch member to engage thelocking member and hold said rigid member at an angle to the horizontal, and a member pivoted to said rigid member and to means fixed with respect to said superstructure to move the rigid member to substantially a horizontal position when the superstructure is in a fully lowered position, movement of said rigid member from the angular position in which it is held by the latch and locking members serving to render said latch and locking members inoperative.

(i. In a hoist, the combination of astationary casing adapted to be substantially buried in the ground, a slidable plunger mounted in said casing, an operating medium for raising and lowering said plunger, load carrying superstructure carried by said plunger, safety mechanism interposed between said superstructure and the ground adapted to be positioned to prevent accidental lowering of said superstructure, said safety mechanism comprising a rigid member pivoted adjacent the upper end thereof to said hoist and of a length less than the distance between the pivot and the ground when the hoist is in fully raised position whereby "when the hoist is inffully raised position the rigid member :is vertically disposed, 'a latch member pivoted to said hoist adjacent 'thepivot of said rigid member, a locking member on said rigid member, said latch memberhaving 'a part cooperating with 'said locking member when said latch member is inoperative to permit the rigid member to engage the ground to prevent lowering of the hoist, said latch member havin a second part movable with said-latch member to engage the locking member and hold said rigid member at'an angle to the horizontal, and a member pivoted to said rigid member and 170- means fixed with respect to said superstructure to move the rigid member toward substantially a horizontal position when the superstructure is being moved toward fully low ered position, movement of said rigid member from the angular position in which it is held by the latch and "locking members serving to render said latch member inoperative by moving the locking member out of engagement with the second part of the latch member and into cooperating relation with the first named part of "the latch member.

5. In a hoist, the combination of a stationary casing adapted to be substantially buried in the ground, a slidable plunger mounted in said casing, operating medium for raising and lowering said plunger, load carrying superstructure carried by said plunger, safety mechanism interposed betweensaid superstructure and the ground adapted to be positioned to prevent accidental lowering of said superstructure, said safety mechanism comprising a rigid member pivoted adjacent the upper end thereof to said hoist and of a length less than the distance between the pivot and the ground when the hoist is in fully raised position whereby when the hoist is in fully raised position the rigid member is vertically disposed, a latch member pivoted to said hoist adjacent the pivot of said rigidmember, a locking member on said rigid member, said latch memher having a part cooperating with said locking member'wlien said latch'niember is inoperative to permit the rigid member to engage the ground to prevent lowering of the hoist, said latchmember having a second part movable with said latch member to :engage the locking member and holding said rigid member at an angle to the horizontal, and a structure interposed between said rigid member and'the ground, said structure comprising telescopically arranged members movable to a predetermined position to form'arigid structure, one of the telescopic members being pivoted operating relation with the first named part of the latch member.

6. In a hoist, the combination of a superstructure, means for raising and lowering said superstructure, safety mechanism movable from an inoperative position when said superstructure is in lowered position to an operative position when said superstructure is raised, said safety mechanism comprising a rigid member pivoted to said hoist by a pivotal connection between said rigid member and hoist, a latch member pivoted to said hoist by a pivotal connection, the axes of said pivotal connections being spaced apart and parallel, said latch member being movable to hold said rigid member in a position other than vertical when said superstructure is raised, and means pivoted to said rigid member for causing said rigid member to pivot around said pivotal connection between the rigid member and hoist to move to inoperative position as the hoist is lowered, said last named means including telescopic members, one of said members being pivoted to said rigid member and the other of said members being pivoted below said rigid member when said rigid member is in inoperatve position with the superstructure lowered, said telescopic members being relatively extensible when the latch is latched and moving to inextensible position to unlatch said latch as the superstructure is being lowered.

CYRUS J. BRISTOL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,387,137 Fisher Aug. 9, 1921 1,691,807 Hollister Nov. 13, 1928 1,872,592 Hott Aug. 16, 1932 1,973,803 Frauen Sept. 18, 1934 1,976,996 Jones Oct. 16, 1934 2,060,753 Cochin Nov. 10, 1936 FOREIGN PATENTS Number Country Date 107,522 Australia May 23, 1939 194,493 Great Britain Mar. 15, 1923

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