US2203872A - Lifting truck - Google Patents

Description

June 11, 1940.. F. e. MAHAFFY LIFTING TRUCK Filed Sept. 5, "1939 Patented June 11, 1940 v UNITED STATES PATENT oFF1cE@.

of the handle.

which the lifting effort to a degree is uniformly Frank Gordon Mahaffy, Toronto, Ontario,

Canada Application September 5, 1939, Serial No. 293,423

9 Claims.

This invention relates. to improvements in lifting trucks of a type comprising a main frame, supporting and steering wheels attached thereto, an elevating frame mounted on the main frame, and a steering and elevating handle.

In the type of lifting truck presently in use the lifting effort required to raise the elevating frame is greatest during the initial swinging movement Trucks have been devised in distributed over .the entire swinging movement of the elevating handle from its initial substantially vertical to its final substantially horizontal position. This result has been attained by means of a complicated mechanism which serves as a connecting means between the. elevating handle and elevating frame. In the latter type of lifting truck it is necessary for the operator to manually disengage the connecting means between the elevating handle and elevating frame after the elevating frame has been raised. F111: thermore, in such previously known trucks, it is difficult or impossible to swing thehandle transversely during the lifting movement in order to avoid an obstruction.

An important object of the present inventio is to provide means whereby the lifting effort is more uniformly distributed over the entire swinging movement of the elevating handle, by a connecting means between the handle and elevating frame which is of a relatively simple constructionas compared to the connecting means in prior use. The object is attained by the use of two connecting elements one of which is swingably connected to the elevating frame; the other of which is pivotally connected to said elevating handle and pivots relative to the handle during the initial lifting movement, and a stop to prevent the last mentioned connecting element from further movement relative to the elevating handle during the latter part of the lifting movement of the handle.

A further object of this invention is to provide a connecting means between the handle and elevating frame of such a construction as to permit thehandle to swing transverselypduring the lifting movement thereofinorder to avoid an obstruction. This object is attained by the use of a connecting means comprising two interengageable members, one of which is mounted on the handle, the other of which is transversely slidably mounted on the elevating frame.

A further object of thisinventionnis to provide .anreffective releasable locking meansbetween the mainframe and elevating'frame. This objectis attained by using a rotatable locking bar, a latch anda lug, extending from the locking bar and engageable by the latch to rotate the locking bar. l

Further objects and advantages of this invention will be apparent during the course of the following description.

i In the accompanying drawing Figure 1 is a perspective front elevation of th lifting truck, showing the elevating frame in its lowered position and the handle upright.

Figure 2 is a. perspective front elevation of the lifting truck, showing the elevating frame in a locked elevated position with the elevating handle lowered. T

Figure 3 is a plan view. of the lifting truck showing the handle in an upright position.

Figure 4 is a fragmentary longitudinalvertical section on the line 4-4 in Fig. 3 on an enlarged scale, showing the connecting means in side ele.

vation.

Figure5 is an elevation of the locking'means showing the relative positions of the members when the elevatingframe is in the lowered position.

Figure 6 is an elevation of the locking means showing the relative positions ofthe members when the elevating frame is in a locked elevated position.

Referring to the drawing, like numerals of 30 reference indicatecorresponding, parts in the different figures in which the assembly of this invention as therein shown includes a main frame I, having front wheels 2, and rear wheels 3, and an elevating frame 4 pivotally conx35 nected to the main frame I by links 5. A steering and elevating. handle 6 is pivotally connected to .the steering head 1 by the pivot pin 8. A rod 8 is pivotally connected to the steering head I and slidably connected to the handle 6 through the lug 6. A compression spring 6 between the lug 6 and a stop on the rod 6 acts as a check to the forwardly and downwardly movement of the handle.

The elevating frame 4 is provided with a cross 5 member 9 which extends transversely between the side members thereof at or near its forward end. .A bracket I0 is mounted on said cross member 9 and a machined bearing shaft ll passes between the two arms of said bracket ll). .59 .One of the connecting elements between the elevating handle and the elevating frame consists I of: a ring 12 which is provided with an extension I2 formed with a machined hole through which the shaft ll extends to swingably and retain thering in a slightly forwardly inclined position.

A hook i5 comprising the other connecting element is pivotally connected to the handle 6 by the pivot pin It. The hook I5 is held in an engageable position with the pivotally mounted ring I2 when the handle is upright, as shown by Figs. 1 and 4, by engagement with the upper end of the king pin or steering column H, which acts as a rest engaging the underside of the hook.

A latch i8, having a recessed underside form ing a hook, is pivotally connected to the elevating frame l. A rotatable locking bar I Elis mounted between the two arms of a bracket 21!! on the main frame i'. A lug 2i and the release pedal 22 pi'ojcctlfrom the locking bar 19 at. approximately right angles to each: other. The lug 2! extends from the bar between the ends thereof, and the pedal 22is of the bridle type, the legs of which are secured to the ends 'of the locking bar adjacent the bracket 2d, and act as guides-for the latch, which rests over the locking bar. A stop 22* extends from the base of the pedal 22 and limits the movement of the pedal by engaging the frame 9 when the pedal is depressed to release the latch.

. In operation, assuming the parts to be in the relative positions as shown in Fig. 1 the ring i2 is swung by the operator to engage the hook it shown in dotted lines in Fig. 4. The handle is then swung forwardly and downwardly. During the initial part of the movement of the handle the hook l5 pivots slightly about the pin Hi.

When the handle has completed about one-half its lifting movement, i.

e.,' after it. has moved through an angle of the hook engages the pivot pin 8 which acts as a stop whereupon the said hook i5 assumes a fixed angular position with respect to the handle t for the remainder of the lifting movement. The effect of this is to more uniformly distribute the lifting strain over the entire swinging movement of the handle.

As the handle approaches its lowest horizontal extremity as shown in Fig. 2, theelevating frame reaches its highest point, and the latch Hi moves forward between the legs of thepedal 22 as shown in Fig. 5, the forward end of the latch engaging the lug 2i rotating the locking bar l9 until the lower surface of the lug 2i engages the surface of the main frame i which acts as a stop to the locking bar. As shownin Fig. 6, the latch i8 falls into place, the forward edge of the hookof the latch assuming a position below the longitudinal axis of the rotatable locking bar l9.

As the elevating frame t is now locked in position as shown in Fig. 2, the operator may now swing the handle back to the vertical, at which position the ring it is freed from the hook l5 and automatically swings back to its original upright position as shown in Figs. 1 and 4. The handle then free and can be pivoted vertically and swung horizontally for steering and hauling purposes.

The descent of the lifting frame i is controlled by the rotatable locking bar i9 and a buffer mech- Ja-n'ism 23. The pedal fi'i is depressed 'causin'gthe merits, one of which is mounted on said handle, "a transverse bearingshaft mounted on the elelug 2| to be rotated by engaging and lifting the latch l8 until the said forward edge of the hook is above the longitudinal axis of the rotatable locking bar. The elevating frame 4 is then free to drop, its descent being checked by the buffer 23. The descent of the frame 4 carries the latch it over the bar l9, until its forward end rests on the bar as illustrated in Figure 5.

The handle may be swung sideways to avoid an obstruction to the forward and downward movement thereof, even though the elevating frame is under load and is partially raised, or the handle may be swung sideways in continuous combination with the forwardly and downwardly movement thereof. As the handle 5 and hook l5 attached thereto, is swung sideways, the machined bearing surface of the ring l2 slides along the machined and lubricated bearing shaft. After, or in combination with the sideways movement of the handle, the operator may continue 2 the forwardly and downwardly movement thereof until the elevating frame is locked in its elevated position. With. the construction shown the handle may be swung sideways'through an angle of 90. v g

.It is to be understood that the form of this invention herewith shownand described is to be taken asa preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without ,3 departing from the spirit of this invention -01 the scope of the subjoined claims.

What I claim as my invention is: a

1. A lifting truck comprising in combination a main frame; supporting and steering wheels 5,31

therefor; a steering and elevating handle; an

elevating frame mounted on said frame; and

means for connecting the elevating frame to said handle comprising two interengageable members,

one of which is mounted on the handle, and a transverse bearing shaft mounted on the elevating frame on which the other interengageable .member is swingably and, slidably mounted.

vertical position to a substantially horizontal position to lift the elevatingframe; and means for connecting said elevating frame to said handle comprising two connecting elements, one of which is swingably connected to the elevating frame, and the other of which is pivotally connected to. said elevating handle and pivots rela- .55

tive to the handle during the initial lifting movement thereof, and a stop adapted to engage the said other connecting element when the handle has completed. part of its lifting movement to preventthe said other connecting element from further pivotal movement relative to said elevating handle during the latter part of the lifting movement of the handle.

3. A lifting truck comprising in combination a main framej supporting and steering wheels .65

therefor;. a steering and elevating handle; an

elevating frame mounted on said main frame;

and means for connecting said elevating frame to said handle, comprising two connecting.ele

vating frame onwhich the other connecting element is swingably and slidably mounted, and

'counterbalancing means for retaining the latter connecting element in position to facilitate en- ,15

gagement and disengagement thereof with the connecting element on the frame.

4. A lifting truck comprising in combination a main frame; supporting and steering wheels therefor; a steering and elevating handle; an

elevating frame mounted on said main frame;

' and means for connecting said elevating frame to said handle comprising two interengageable elements one of which is pivoted tosaid elevating handle and pivots relative to the handle during the initial movement thereof, a stop to prevent the said interengageable element from further movement relative to said handle during the latter part of the lifting movement of the handle, a transverse bearing member mounted on the said elevating frame, on which the other inter- 1 engeable element is swingably and slidably mounted, and counterbalancing means for retaining the latter connecting element in position to facilitate engagement and disengagement thereof with the connecting element on the frame.

5. A lifting truck comprising in combination a main frame; supporting and steering wheels therefor; a steering and elevating handle; an elevating frame mounted on said main frame;

a steering column, including a bracket; a pivot pin on said bracket on which the steering handle pivots; a connecting member pivoted to the handle; and a connecting member on the elevating frame adapted to be engaged by the connecting member on the handle, the connecting member on the handle being so constructed and arranged relative to the pivot pin for the handle,

that the said. connecting member engages the said pivot pin after the initial lifting movement of the handle and remains in engagement during the final lifting movement thereof.

6. A lifting truck comprising in combination a main frame; supporting and steering wheels therefor; a steering and elevating handle; an elevating frame mounted on said main, frame; means for lockingsaid elevating frame in a fixed elevated position,such means'comprising a vertically swingable latch connected to one of the frames and a rotatable locking bar connected to the other frame and adapted to be engaged by the latch, a lug extending from one side of said rotatable lockingbar and adapted to be engaged by the latch to rotate the locking bar, and means for rotating the bar to cause the lug to engage the latch and lift it out of engagement with the locking bar.

'7. A lifting truck comprising in combination a main frame; supporting and steering wheels therefor; a steering and elevating handle; an elevating frame mounted, on said main frame; and means for releasably locking said elevating frame in a fixed elevated position comprising a vertically swingable latch, a rotatable locking bar, a lug extending from said rotatable locking bar and adapted to be engaged by the latch to rotate the locking bar, a vertically swingable latch, and a pedal extending upwardly from the rotatable locking bar and movable to rotate the bar to cause the lug to engage the latch and lift it out of engagement with the locking bar.

8. A lifting truck comprising in combination a main frame; supporting and steering wheels therefor; a steering and elevating handle; an elevating frame mounted onsaid main frame; and means for releasably locking said elevating frame in a fixed elevated position, such means comprising, a rotatable locking bar, a vertically swingable latch, and a bridle type pedal extending upwardly from the locking bar, the sides of said bridle type pedal acting as guides for the vertically swingable latch.

9. A lifting'truck comprising in combination a main frame; supporting and steering wheels therefor; a steering and elevating handle; an elevating frame mounted on said main frame; and means for connecting the elevating frame to said handle comprising two interengageable FRANK G. MAHAFFY.

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