US1243844A - Safety device for ladders. - Google Patents

Description

R. W. LOFSTROM.

SAFETY DEVICE FOR'LADDERS.

APPLICATION FILED MAR. 28, I917.

Patented Oct. 23,1917.

314mm ROBERT .W LOFSI'ROM atmnq Y a sa -a ribs.

- ROBERT w. LOFSTROM, OF woRoEs'rEn, MAssAoHiIsETrs.

SAFETY DEVICE FOR LADDERS.

' Devices for Ladders, of which the following is a specification, referenc'e being had to the accompanying drawings.

This invention relates to an improved safety device for ladders and has for its pr mary object to' provide a very simply and durably constructed ladder attachment whereby. the ladder will be securely held against accidental shifting movement upon the floor or ground surface and possible injury to the person ascending or descending the ladder thus obviated.

It is' one of the important objects of the invention to provide a device for the above holding plate 11 is preferably of triangular form, as shown,*and therbase edgefthereofpurpose which will effectively operate to hold the ladder inpos'ition upon a metal or concrete floor, as well as upon wooden floors.

'More' particularly. stated, the invention embodiesan attachment for each of the ladder rails consisting of 'fixed'body plates and i an anchoring or holding device pivotallyof frictional contact of the edge of vtheplat'e disposed upon opposite sides of-the pivotal axis thereof, when theladder.issetinposition upon a metalor.concrete'fioorsurface mounted between the body plates,,said anchoring plates being adjustable to different relative positions for properly supportingthe ladder upon a metal,concrete, or wood floor surface, and'means mounted upon the j body plates with which said holding plates are adapted to engage to prevent the accidental movement of the latter from' their adjusted positions.

With the above and other objects in view, my invention consists in the novel features of construction, combination and arrange- -ment of parts to be hereinafter-more fully described, claimed and'illustrated in'the ac'g companying drawing, in which, 1

Figure .1 is a side elevation showing my improved safety device applied to the lower end of a ladder rail, several adjusted positions of they holding plate being illustrated in dotted lines;

Fig. 2 is a front, elevation of the attachment;"and i Fig. 3 is asectiontaken on the line 33 of Fig. 1. 1 v 5 Fig. 4 is a side elevation illustrating a j J slightly modified form of the device; and

H Referring in detail to the drawing, 5;-

Fig. 5 is a section taken on the line 5-5 of Fig. 4.

Specification of Letters Patent.

prevent Patented Oct. 23, 19 17.

. Application filed. March 28, 1917. Serial No. 158,008.

designates a pair of metal. plates are arranged uponyeach other and. securely;

boltedat one of their ends, as at 6,.to'the outer side of the ladder rail. B. 'These plates project below the. lower end of the rail R and are transversely ofiset in relav ti'vely opposite directions, as shown at 7, to space apart their lower end portions 8. .The ofi'sets 7, at opposite sides of the central line of the plate, are obliquely extendedv in relatively opposite directions to the longitudinal edges of the plate, whereby inclined bearing shoulders 9 are formed. Adjacent to these bearing shoulders, the two plates 5 are permanently riveted together,as at 10.

Between the lower spaced end portions of the plates'8, the anchoring or holding plate 11 is disposed and-engaged for pivotal movement upon a bolt 12 connecting said spaced portions 8 of the body plates. .This

is longitudinally recessedfor cut away, as at 13', said recess terminating. before' it 'reachesthe points or apice's 14 of the plate. Thus, thespaced apart foot portions 15 are formed, which provides spaced apart points tions with respect to the 7 body plates and normally'restupon the outer ends of the oifsets 7in the body plates.

' When the ladder is used upon a wooden floor surface, the plates 14 may be turned to the'positions indicated in dotted lines at A in Fig. 1, sothat-one of the points 15 will be in the vertical lineof the pivot 12.. One of the loops 16 is then engaged over the other point 14 ofthe plate to hold said plate in this adjusted position. ;The downwardly projecting point 14 of the plate will embed itself inthe floor'surface under the weight of the person ascending the ladder and thus shifting movement f the same, or the plate may be disposed in the dotted line by means of the bolt 12'.

position B, with one of its points 14 disposed in advance of the pivot 12 and the other of the loops 16 engaged over the other point of the plate. Should the floor 'sur face be uneven, the plate 11 at one side of the ladder may be disposed in position A, while the plate on the opposite side of the ladder is disposed in position B. It is to be particularly noted that in. either of these latter positions of the plate 11, the same abuts against the shoulders 9 on the body plates, and there is no strain upon the loops 16 or the pivot connections 17 thereof, said loops simply acting as stops to prevent an outward swinging movement'of the plate 11 with respect to theshoulders 9 and also to prevent the accidental displacement of the plate by falling objects striking its upwardly projecting point or by striking the same with the foot when descending the ladder. These loops also retain the plates 11 in their adjusted positions when the ladder is moved from place to place.

Referring now to Figs. 4 and 5 of the drawing, wherein I have shown a slightly modified form of the device, 11 designates the holding or anchoring. plate which is similar in configuration to the anchoring plate above described. One of the plates 11, however, is adapted to be secured to the upper end of each of the ladder rails upon either the inner'or outer face thereof,

In order to securelyhold the plate 11 andprevent turning movement of the same upon or with the bolt 12, an opening ispunched in the plate with a suitable tool to project the metal from one face of the plate,:as shown at 20. This projection is disposed inline with the bolt receiving opening in the plate and is adapted to be embedded inthe ladder rail, as clearly shown in Fig. 5 of the draw- In order to prevent splitting of the rail, a boltindicated at 21 maybe inserted transversely through the upper end thereof.

This modified'form of the anchoring plate is particularly adapted for the purpose of holding the upper end of the ladder against either vertical or lateral movement with respect to the face of a wall or post against which the ladder is disposed, and also to afford further securitywhen the ladder is used upon a very hardand smooth floor surface to prevent displacement of the ladder in case the lower end portion thereof should he accidentally struck.

In Fig; 4, I have shownathe ladder. dis

posed at its upperend against a rod on shaft S running along theface of the wall :indicated at lV. One end .or'the other of the plate 11, according to whether this plate is arranged upon the inneror outer face of the'ladder rail, is disposed 'overand upon the shaft "S andthe point of the plate is embedded in the wall face, Thus, the

ladder at its upper end will be effectually held against either vertical or lateral shifting movement. It will, of course, be understood that in either form of the plate 11, the lower edges of its foot portions 15 may be toothed or otherwise formed in order to obtain a more securely gripping engagement with the surface.

From the foregoing description, taken-in connection with the accompanying drawing, the construction, manner of use, and several advantages of the device will bevclearly and fully understood. It will be seen that I have provided a very simple and durably constructed ladder attachment whereby the ladder is effectively held against shifting or sliding movement either upon psmooth, concrete, or metal floors, orupona wood floor. ,The holding plates may be very easily and quickly adjusted in orderto properly position the ladder. In view of" the very simple construction of the attachment, it is also manifest that the same can be produced at small manufacturing cost.

WVhile I have herein shown and described the preferred construction and arrangement of the severalelements employed, it is apparent that the same are susceptibleof considerable modification and I, therefore,.reserve the privilege of adopting all such legitimate changes as may be fairly embodied within the spirit and scope of the invention as claimed. 7

Having thus fully described my invention, what I desire to claim and secure: by Letters Patent isf l. A device of .the character described comprising a pivotally mounted, triangular fioor engaging plate having spaced points for engagementwith the floor surface, -and means to operatively engage one of the points of said plate and ,holdflthe other in vertical alinement with the pivot .o fzthe plate for operative engagement with the floor surface. a

2. A holding device of the: character described comprising a relatively fixed body, a holding plate movably mounted upon said body and having .spaced floor engaging points, saidplate being adjustable with re spect to the body to position eitherof said the body to engage the plate. andhold the same against said stop shoulders.

4. The device recited inclaim 2,,fu'rther characterized by latch loops pivoted upon the body for engagement with the inactive point of said plate in the operative; position of the plate.

A holdingdevice for ladders including a pair of plates bolted to the ladder rail and being offset to space the plates apart at one of their ends, a holding plate pivotally mounted between the spaced ends of the body plates and adjustable to various positions between said body plates for operative engagement with the floor surface, and latch devices mounted upon the body plates to engage the holding plate in certain of its operative positions and prevent pivotal movement thereof. V

6. A holding device for ladders including a pair of body plates fixed to the lower end of the ladder rail and having ofl'set portions to space said plates apart at one of their ends, said offset portions providing stop shoulders, a holding plate of polygonal form pivotally mounted between the spaced ends of the body plates and adjustable therebetween to various positions for operative engagement with the floor, said holding plate in certain of the operative positions thereof bearing against the stop shoulders which limit the pivotal movement of the'plate in one direction, and latch elements mounted upon the body plates to coact with the holding plate in such operative positions of the plate and prevent pivotal movement of said holding plate in an opposite direction.

7. A device of the character described comprising a substantially triangularshaped plate, an attaching bolt therefor, and means for holding the plate against pivotal movement with respect to the part to which it is attached, whereby either one of two spaced apices of the plate may be disposed in operative position with respect to said part.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses.

ROBERT W; LOFSTROM.

Witnesses:

OPAL Y, GIFFERTS, CARL B. BRUSON.

copies of this patent may'be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. O.

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