US1961289A

US1961289A - Safety ladder attachment

Info

Publication number: US1961289A
Application number: US661611A
Authority: US
Inventors: Thomas E Gardner
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-03-18
Filing date: 1933-03-18
Publication date: 1934-06-05
Anticipated expiration: 1951-06-05

Description

June 5, 1934. T E, GARDNER 1,961,289

SAFETY LADDER ATTAGHMNT Filed March 18, 1935 l2 Sheets-Sheet. l

'o ,yp i@ wwf;

ltorney June 5, 1934. T, E GARDNER 1,961,289

SAFETY LADDER ATTACHMENT Filed March 18, 1935 2 Sheets-Sheet 2 45] Inventor 4f E vzdrzzer 45 /f P47 By Patented June 5, 1934 Unirse STATES PATENT OFFICE SAFETY LADDER ATTACHMENT Thomas E. Gardner, Waterville, N. C.

Application March 18, 1933, Serial No. 661,611 cclaims. (o1. 22S- 61) The present invention relates to improvements in safety ladder attachments and has reference more particularly to an implement that is principally used by electricians.

It has been the universal practice, in the use of ladders on wood or steel poles to have an assistant on the ground to attempt to hold or help support the ladder in order to minimize the hazard to the man that works on top of the 19 ladder. To obviate the necessity of an extra man to steady the ladder, in some cases ropes are used to tie the top of the ladder fast to the top of the pole, in which case there is. the hazard of climbing to the top of the ladder as well as the risk of tying the rope to the ladder and pole. Then again, it is very difficult to make a ladder rigid and secure by tying the same to a pole.

In cases Where an extension is used on lad- 20 ders, it is almost impossible for a man on the ground to prevent the ladder from sliding or twisting at the top of the pole which may very easily throw a man at work on the ladder off balance, causing him to come in contact with high voltage equipment, causing injury not only to himself but to the man on the ground who is in danger from falling tools or equipment.

By using the safety ladder attachment of the present invention, anextra man is eliminated from the payroll and at the same time reducing the liability of the company to accidents among the employees.

Another object of the invention is to provide a device to eliminate such hazards as extension supports, releasing or failing to hold the upper part of the ladder, or perhaps giving away on account of a broken rung allowing the ladder to fall thereby causing serious damage to life or property. Moreover the attachment of the present invention will prevent the ladder from riding up the pole in event an automobile or other vehicle should back into the ladder and exert an upward pressure on the bottom of the ladder; and at the same time the ladder will remain substantially stationary from the impact, thereby overcoming injury to the workman on the ladder.

Another object of equal importance is to provide means to secure the ladder fast to the pole should the party using the ladder desire to leave the same to mount some other structure, as well as descend to the ground in quest of tools or equipment.

A further advantage of the invention is to o be able to make the ladder fast to the pole in a substantially vertical position before mounting the same, with means for releasing the same from the ground when desired.

It will thus be seen from the foregoing that I have provided a device that is adapted for a particular purpose, namely, in preventing accidents, removing hazards, and a considerable time and a money saver and due to the simplicity of the device it will form a compact, as well as a positive and convenient device.

I am aware of prior patents that utilize the lateral clamping jaws but there is a certain flexibility in the locking arrangement which allows side play to a certain degree and more especially, when the linemen shift their weights to and from the top of the ladder which often occurs, where they are required to step to and from Ythe cross arms of the pole upon which they are operating.

The major portion of this difficulty I overcome by providing a third point of contact by a gripping plunger head midway between the lateral clamping jaws, which furnishes a positive locking means controlled from the top of the laddeigwhereby the lateral clamping jaws together with the griping plunger head are locked in embracing relation about the pole; and moreover, I construct the device so that it can be transferred with ease and dispatch from one ladder to another.`

Further objects of the invention are to provide an attachment of the character referred to that is strong, compact and durable, thoroughly reliable in its operation, very simple to assemble and repair, and is comparatively inexpensive to manufacture and install.

With the foregoing and other objects and advantages in view, the invention consists. of a novel construction, combination and arrangement of parts, as will be hereinafter more fully described in the accompanying drawings and specification wherein is disclosed a preferred embodiment of the invention, but it is to be understood that changes, variations, and modirlcations may be resorted to Without departing from the spirit and scope of the invention in A' the subjoined claims.

In the drawings wherein like reference characters denote corresponding parts throughout the several viewS:-

Figure 1 is a side elevation of a pole showing in side elevation a ladder coupled to the pole by the attachment of the present invention.

Fig. 2 is an enlarged section taken substantially on line 2 2 of Fig. 1, showing in top plan View the invention in locked relation. Fig. 3 is a top plan View of the attachment in released relation.

Fig. 4 is a longitudinal section taken substantially on line 4-4 of Fig. 3.

Fig. 5 is a vertical section through the frame taken substantially on line 5-5 of Fig. 3.

Fig. 6 is vertical section through the frame taken substantially on line 6-6 of Fig. 1.

Fig. 7 is a perspective View of the plunger. Fig. 3 is a fragmentary vertical section thru the frame taken substantially on line 3,-8 of Fig. 3.

Figure 9 is a detailed vertical section taken substantially on line 9--9 of Figure 2.

Fig. l0 is an enlarged fragmentary elevation i the inner end of the plunger. Referring to the drawings, H indicates a hollow iron pole, although it may be of wood, standing upright and supported in the ground G. Resting on the ground is a ladder L which is coupled in slightly tilted Yrelation to the pole by the ladder attachment of the present invention indicated at A. The ladder attachment consists of a U-shaped metal frame including a crown portion 9 and side legs 1 0-11 merging with the crown at their forward ends. To reinforce the frame and also form a rear bearing for the plunger P, to be presently described, a cross brace l2 bridges the legs 10-11 and has its ends rigidly secured to an intermediate portion of said legs. On the free end, each leg of the frame is formed with a bearing ring 13 straddling which are a pair of spaced apertured wings 14 secured to and projecting horizontally from the forward portion of loop 15 of the hanger bar S, there being one hanger bar for each leg of the frame.

Each hanger bar S consists oi an upper loop 15 that slips over a rung 18 preferably at the top oi the ladder. Formed integral with the loop is a depending arm 16 that extends to the next lower rung 19 and the arm terminates in an inwardly iaied lip 17 that bears against the inside of the rung 19. The hanger bar is formed of metal and there is a certain degree of ilexibility in arm 16 to facilitate the attachment or removal from the rungs of the ladder so that the entire attachment may be easily transferred to different ladders. When the hanger bars are attached to the ladder the set screws 20 mounted in the wall of loop l5 may be tightened* to grip the rung 18 and thereby anchor the hanger bars to the ladder. It will be understood that the hanger bars nt between the standards of` the ladder as will be clearly understood from Fig. 1 of the drawings which show the attachment coupled to the ladder.

A bolt 21 extends through each pair of apertured ears 14 on each hanger bar and the ring 13 on which the frame F swings. A portion of the bolt 21 between the ring 13 and one of the ears 14 supports the coil spring 22 and Vone end 23 of each spring is clinched to an ear 14, while the other end 24 extends under and is clinched to the respective legs of the frame, as is clearly shown in Fig. 6 of the drawings. The tension of coil springs 22 is suicient to balance the weight of the frame and support said frame in a horizontal position under ordinary conditions in readiness for encircling the pole. However, when it is desired to store the ladder, the frame may be folded upwardly in line with the ladder in which position it will remain until returned manually to the horizontal position. On the other hand, in sliding the attachment up the pole, any obstacles encountered such as foot spikes will swing the attachment downwardly against the tension of the springs and when the obstacle is cleared the attachment will again assume the horizontal position.

1n the crown 9 of the frame F there are a pair of lateral elongated,

horizontal slots

25, 26 and a smaller intermediate slot 27. A relatively flat intermediate portion 28 of the plunger P slides through the central slot 27 while a reduced threaded portion 29 is slidably supported in and extends through the smooth bearing opening 30 in the center of brace l2. Rearwardly of the brace there is threadably mounted on the rear portion 29 the turn buckle handle 31. On the extreme end of the threaded portion 29 is mounted an eye bolt 32 to which a rope may be attached for releasing or locking the attachment from the ground. A portion of the plunger extends iorwardly of the crown 9 on which is i'ormed the segmental gripping head 33 formed with an arcuate serrated forward face 34.

Between the crown 9 and the brace 12 there is pivoted as at 35 the intermediate portion of a cross bar 36. There is enough play to permit cross bar 38 to swing slightly on the pivot 35. There are two clamping arms on the attachment, each of which includes a substantially fiat, straight

rear portion

37, 38 which extend through the

respective slots

25, 26 on the crown 9 or" the frame. The rear ends of

portions

37, 38 are pivoted to the opposite ends of the cross bar 36 as at 39, 49. The clamping arms on their forward ends are made with arcuate clamping jaws 41, 42 which are integral with the

straight portions

37, 38, and the clamping jaws extend outwardly from the crown 9 of the frame. On the confronting faces, the arcuate clamping jaws are serrated as at 43 so that they will bite into the metal or wooden pole. A coil spring 44 encircles the threaded portion 29 of the plunger P and one end bears against the cross bar 36 while the rear end bears against the brace 12. The coil spring 44 has enough tension to maintain the clamping jaws 41, 42 in open position as shown in Fig. 3*"when the other parts are in released position. When the plunger P is moved in or out the edge of the

straight portions

37, 33 fulcrum against the outer edges of the

respective slots

25, 26. To enable the attachment of the present invention to be adapted to poles of smaller circumference I provide one or more vertical openings 45 forv each slot 25-26 in the crown 9 of the frame. When smaller poles are encountered, a pin 46 may be inserted in the openings 45 and locked by the cotter pin 47 to change the fulcrum of the gripping arms.

1n using the attachment of the present invention, it is in the released position as shown in Fig. 3 when the lineman wishes to couple the ladder to the pole. The ladder is raised to a Vertical position with the pole between theclamping jaws 41, 42. Then the rope (not shown) is pulled from the ground which action causes clamping jaws 41, 42 to grip the pole and the plunger head 33 to do the same. Then the rope may be tied to the bottom rung of the ladder whereupon the lineman is ready to ascend. As he reaches the top, the turn buckle handle 31 is turned clockwise until suflicient pressure is brought to bear by the clamping jaws and the plunger head. When the lineman descends the ladder turn buckle handle 31 is 1,961,289 turned counter clockwise but since the rope isstill attached to the bottom rung, the ladder will remain in fast coupled relation to thepole until the lineman reaches the ground whereupon the rope may be untied and the clamping jaws 4l, 42 under the tension of the coil spring 44 will release.

Having thus described my invention, what I claim as new is:-

1. A ladder attachment comprising a hanger bar adapted for coupling to a ladder, a frame pivoted to the hanger bar, a plunger yieldingly mounted in the frame, a pair of clamping arms movably mounted in the frame and pivotally connected to an intermediate portion of the plunger, said plunger formed with a gripping head disposed between the clamping arms to provide a third point of contact, and means on the plunger for positively locking the plunger and clamping arms in clamped relation about a pole.

2. A ladder attachment comprising a hanger bar adapted for coupling to a ladder, a frame pivoted to the hanger bar, a plunger yieldingly mounted in the frame, a pair of clamping arms movably mounted in the frame and pivotally connected to an intermediate portion of the plunger, said plunger formed with a gripping head disposed between the clamping arms to provide a third point of contact, means on the plunger for positively locking the plunger and clamping arms in clamped relation about a pole, and said frame being of U-shaped coniiguration including a crown and a pair of legs, and intermediate portions of said plunger and clamping arms extending through said crown.

3. A ladder attachment comprising a hanger bar adapted for coupling to a ladder, a frame.

pivoted to the hanger bar, a plunger yieldingly mounted in the frame, a pair of clamping arms movably mounted in the frame and pivotally connected to an intermediate portion of the plunger, said plunger formed with a gripping head disposed between the clamping arms to provide a third point of contact, means on the plunger for positively looking the plunger and clamping arms in clamped relation about a pole, and said frame being of U-shaped conguration including a crown and a pair of legs, intermediate portions of said plunger and clamping arms extending through said crown, and a cross brace bridging the legs of said frame and formed with a bearing in which is. slidably mounted the rear portion of the plunger.

4. A ladder attachment comprising a hanger bar adapted for coupling to a ladder, a frame pivoted to the hanger bar, a plunger yieldingly mounted in the frame, a pair of clamping arms movably mounted in the frame and pivotally connected to an intermediate portion of the plunger, said plunger formed with a gripping head disposed between the clamping arms to provide a third point of contact, means on the plunger for positively locking the plunger and clamping arms in clamped relation about a pole, said frame being of U-shaped conguration including a crown and a pair of legs, intermediate portions of said plunger and clamping arms extending through said crown, a cross brace bridging the legs of said frame and formed with a bearing in which is slidably mounted the rear portion of the plunger, and means on the hanger bars adapted for detachably connecting said hanger bar to a ladder.

5. A ladder attachment comprising a frame adapted for connection to a ladder, a plunger including a gripping head movably carried by the frame, a pair of lateral clamping arms connected with the plunger and bearing on the frame, and means coacting with the plunger and the frame for locking the plunger and lateral clamping arms in embraced relation about a pole.

6. A ladder attachment comprising a frame adapted for connection to a ladder, a pair of lateral clamping members and an intermediate gripping member movably carried by the frame, and means coacting with one of said members and the frame for locking all of said members in embraced relation about a pole.

THOMAS E. GARDNER.