Safe inclination indicator for ladders
US 3118234 A
Description (OCR text may contain errors)
Jan. 21, 1964 w. J. WILSON SAFE INCLINATION INDICATOR FOR LADDERS Filed Nov. 18, 1960 INVENTOR. Wi l llum J. W||son BY M United States Patent 3,118,234 SAFE EHCLINATHON INDECATOR 'FGR LADDERS William J. Wilson, 66 Oak Crest Road, W est Orange, NJ. Filed Nov. 18, 1969, Ser. No. 76,351 4 Claims. (ill. 33-207) My invention relates generally to indicators, and specifically to safe inclination indicators for ladders.
It is among the objects of my invention to provide a safe inclination indicator for a ladder that will surely indicate the safe angle of inclination for the ladder at all times, and will not bind or stick so as to give a false reading.
It is another object of my invention to provide a safe inclination indicator that is accurate and sturdy.
A still further object of my invention is to provide a safe inclination indicator which is easy to attach and detach.
These objects and advantages as well as other objects and advantages may be achieved by the device shown by way of illustration in the drawings in which:
FIGURE 1 is a front perspective view of the housing detached from the base;
FIGURE 2 is a front view of the plumb;
FIGURE 3 is a side view of the plumb;
FIGURE 4 is a vertical sectional view of the assemblage taken on the line 4-4 in FIGURE 5, looking in the direction of the arrows;
FIGURE 5 is a front elevational view of the assemblage attached to a ladder side-rail;
FIGURE 6 is a bottom view of the device attached to the side rail of the ladder; and
FIGURE 7 is a view of a ladder disposed against a wall with my safe inclination indicator attached.
The happening of accidents in the use of ladders is very frequent due to the failure to position the ladder at the angle with respect to the wall at which the tendency of the top of the ladder to pivot outwardly, or the bottom to slide outwardly, is minimized. it has been determined that the safest angle of inclination of a ladder is approm'- mntely 75 from horizontal. The present device provides a plumb housing with an indicator movable in response to the 'mfluence of gravity to coincide with an index mark, when the ladder to which the housing has been attached, is inclined at the safe 75 angle. The plumb is provided with tracking means so that it will at all times be freely responsive to gravitational attraction and will not stick or bind so as to give a false reading.
Referring now to the drawings in detail, my safe inclination indicator for ladders has a housing 11 which is generally triangular in shape with a bottom wall and integral side walls 12, 12 on the other two sides. The housing 21 has a side 13 slot in each of the side walls 12, 12. It also has a front slot 14 which is generally arcuate. Near the apex of the triangular housing 11, there is a hole 15 to admit an axle 16. The front of the housing 11 is provided with an index mark 17 indicating the position that will be registered by the indicator when the ladder to which the device is attached is disposed at a safe angle. The legend out may be shown on one side of the index mark 17 so that when the indicator points toward it, the ladder must be moved outwardly. The legend in may be shown on the other side of the index mark 17 so that when the indicator points toward it, the ladder must be moved inwardly. The word safe can be shown at the index mark '17.
A base 18 is provided for mounting the housing 11. The base has a threaded aperture 19 to engage the threaded end of the axle 16, thereby to engage the housing 11 and the base 18 together. The base 18 has a pair of legs 2 3, 26 extending from one side; each leg 20, 20 is provided with a generally perpendicular rcarwardly ex- "ice tending offset 21, 21 that will engage the side-rail of a ladder 25. On the opposite side of the base 13, there is another leg 22 which has an offset 23 at the end. This offset 23 has a threaded passage to receive a thumbscrew 24 by which clamping means the base 18 is secure to the side rail of the ladder 25.
A plumb 26 is provided for pivotal suspension in the housing ll. The plumb 26 freely rotates on the bearingboss 27 which has an axle passage. The axle 16 carries the bearing boss 27 so that the plumb 26 may pivot thereon in response to gravitational attraction. The plumb 26 has arcuate wings 28, 28 extending sidewardly and in an are defined by a radius sufiicient to permit them to slide freely in the side slots 13, 13. The front of the plumb 26 has a small, generally horizontal shaft 29 upon which the indicator 30 is mounted. The shaft 29 is sufficiently long so that it extends through the front slot 14 and the indicator 30 is outside the housing 11.
In the present safe inclination indicator, the indicator 3%) pointer is at all times freely responsive to the force of gravity due to the bearing boss 27 mounted on the axle 16, and the arcuate wings 28, 28 in the slots 13, 13, so that a true reading of inclination is at all times obtained without the binding of the indicator which would give a false reading, to the danger and detriment of the user of the device.
The foregoing is intended to be merely illustrative of the general form of my invention, for many changes may be made in the selection and arrangement of the various parts within the scope of the claims without departing from the spirit of the invention.
What is claimed:
1. A safe inclination indicator for ladders comprising a housing having a pair of opposite side slots and an arcuate front slot,
at base, offsets on opposite sides of the base, a thumbscrew in threaded engagement with one of the offsets and adjustable in the direction of the other offset,
an axle connecting the housing to the base,
a gravitationally influenced plumb pivotally mounted on the axle in the housing, arcuate wings on the plumb movable in the side slots as the plumb pivots in the housing, an indicator on the plumb extending through the arcuate slot in the front of the housing,
an index mark on the outside of the housing adjacent to the arcuate slot defining with relation to the indioator the safe inclination of a ladder to which the base is attached.
2. A safe inclination indicator for ladders comprising a housing,
a means for attaching the housing to a ladder,
a gravitationally influenced plumb mounted in the housing, portions of the plumb extending through slots in the housing, an indicator on the plumb extending through a slot in the housing,
an index mark on the outside of the housing in coincidence with the indicator when a ladder to which the housing is attached has an angular disposition of from horizontal.
3. A safe inclination indicator for ladders comprising a generally triangular housing, a front wall on the housing, a side wall in three sides of the front wall with a pair of opposite slots in the side wall, an arcuate front slot in the front wall,
a base complementary to the housing, a pair of offsets on one side of the base, an offset on the opposite side of the base, a thumbscrew in threaded engagement with one of the offsets and adjustable in the direction of the other offset,
a bolt connecting the housing to the base and defining an axle,
4. A safe inclination indicator for ladders comprising 10 (a) the combination of a ladder with,
(b) a housing,
(c) a front wall on the housing having a generally arouate slot,
(d) opposite intersecting side walls on the housing having a pair of generally vertical, opposed slots therein,
(2) a base complementary to the housing,
(1) a pair of offsets on one side of the base engaged .with the ladder,
(g) an offset on the opposite side of the base,
(It) a thumb screw in threaded engagement with the offset on the opposite side of the base and adapted to frictionally engage the base to the housing (i) a bolt connecting the housing to the base and defining an axle for a plumb (j) a gravitationally influenced plumb pivotally mounted on the axle (k) arcuate Wings on the plumb extending through the generally vertical, opposed slots in the side Walls of the housing (I) an indicator on the plumb extending through the arcuate slot in the firont wall of the housing (m) the housing positioned with respect to the ladder with the center of the arcuate slot generally coincident with the plumb 'When the ladder is inclined at an angle of 75 from the horizontal (n) index marks on the housing defining the limits of safe inclination of the ladder as defined by the plumb.
References liter in the file of this patent UNITED STATES PATENTS 1,110,026 Zars Sept. 8, 1914 1,239,336 Bair et al. Sept. 4, 1917 1,618,237 Sturm Feb. 22, 1927 2,495,765 Rauscher Jan. 31, 1950 2,845,719 Thomiszer Aug. 5, 1958