US2884144A - Material handling apparatus - Google Patents

Description

April 28, 1959 R. J. LAWS 2,884,144

MATERIAL HANDLING APPARATUS Filed June 29, 1956 4 Sheds-Sheet 1 7 INVEINTOR. ROBE/er .ZAWS

4rme-ys IN VEN TOR.

, April'28, 1959 R. J. LAws 2,384,144

MATERIAL HANDLING APPARATUS Filed June 29, 1956 4 Sheets-Sheet 2 R. J. LAWS MATERIAL HANDLING APPARATUS April 28, 1959 4 Sheets- Sheet 3 Filed June 29, 1956 w wt.

INVENTOR. FOBERT J: W

' I BY 1 f A'rraelvsys April 28, 1959 R. J. LAWS 2,884,144

MATERIAL HANDLING APPARATUS Filed June 29, 1956 -4 Sheets-Sheet 4 INVENTOR.

"Unimd States P O,

MATERIAL HANDLING APPARATUS Robert J. Laws, Parkview Village, Ohio, assignor, by mesne assignments, to Otis Elevator Company, New York, N.Y., a corporation of New Jersey Application June 29, 1956, Serial No. 594,999

12 Claims. 01. 214-1 The present invention relates to a material handling device and, more particularly, to a floating load support which is capable of movement in a plurality of directions from a static load-supporting position in response to a deflecting force applied to the load support or load thereon.

One of the important objects of the present invention is the provision of a new and improved floating load-supa Another object of the present invention is the provision of a new and improved load-supporting device for supporting a member to be registered or aligned with another member, which device is yieldable in response to a deflecting force applied to the load member to permit the load to be yawed, pitched, or moved along a vertical plane or horizontal plane, or rolled about a horizontal axis, or moved along a path which is a resultant of the movements set forth, depending upon the direction of the applied force.

A further object of the present invention is the provision of a new and improved floating type load support which is resiliently urged to a normal load-supporting position by biasing means operatively connected to the load support through a linkage which permits the biasing means to support a relatively heavy load in a normal static posi-- tion, but yet permits a relatively large movement of the load support against the action of the biasing means in response to a force applied to the support, the linkage being arranged so that the force necessary to depress the load support against the biasing means does not become unduly large within the range of movement of the load .support and, preferably, remains substantially constant throughout the range of movement.

Another object of the present invention is to-provide a floating type load support which is movable in a generally vertical direction and which may be rocked about a generally horizontal axis and which includes resilient means for yieldably opposing the rocking and vertical movements of the load support.

The invention resides in certain constructions, combi- I nations and arrangements of parts and further objects and advantages thereof will be apparent from the following detailed description of the preferred embodiment made with reference to the accompanying drawings forming a part of this specification and in which:

Fig. 1 is a side elevational view of a load-supportin device embodying the present invention supported thereon;

Fig. 2 is a side elevational view of the central portion of the load-supporting device shown in Fig. l;

2,884,144 Patented A r. 28, 1959 Fig. 3 is a plan view of the portion of the load-supporting device shown in Fig. 2;

Fig. 4 is a sectional view taken approximately along the line 4-4 of Fig. 3;

Fig. 5 is a sectional view taken as indicated by the section line 55 of Fig. 3;

Fig. 6 is a sectional view taken approximately along line 66 of Fig. 3;

Fig. 7 is a fragmentary plan view looking from line 7-7 of Fig. 2;

Fig. 8 is an enlarged fragmentary view of a portion of Fig. 2 showing the details of the latch for holding the load support against movement in a horizontal plane; and

Fig. 9 is a simplified perspective view, somewhat diagrammatic, of a load support of the device of Fig. l.

The load-supporting device of the present invention is susceptible of various modifications and constructions and of use with various apparatuses for handling loads. In the preferred and illustrated embodiment, the load-supporting device A comprises an elongated bed or frame B of truss construction and having spaced load supports 10, 11, 11'

thereon which are adapted to support an elongated load struction which permits it to be collapsed to an out-of-the- ,way position, while the load support 11 is preferably positioned on the bed B so as to be under the center of gravity of the load to be handled, and the load support 11' is at the end of the bed remote from the support 10. While various types of loads may be handled by the illustrated load-supporting device, the particular load member shown in the drawing is a beam 12 having a bracket 13 welded to the upper side thereof, which bracket is to be registered or aligned with a receiving member or bracket, not shown in the drawings.

The bed of the load-supporting device A has spaced vertical plates 17, 18 fixed to the upper side thereof so as to extend parallel of the length of the bed. The plate 17 has openings 19, 20 therein at the opposite ends thereof and the plate 18 has openings 19', 20' aligned with the openings 19, 20, respectively. The openings 19, 19, 20, 20' are adapted to receive the fork members, not shown, of an industrial lift truck and provide a convenient means for handling the device. It will be understood, of course, that the device may be handled in any convenient manner.

The fork members of the truck are inserted into the openings 19, 19 and 20, 20 and are clamped against the upper sides of the openings by clamp plates 21, 22 supported in the. openings 19, 19' and 20, 20', respectively.

The clamp plate 21 is pivotally supported for selfaligning movement by a pin 23 extending between, and supported by, arms 24, 25 respectively extending along the outer sides of the plates 17, 18, parallel to the length of the bed and pivotally connected at their ends inwardly of the openings 19, 19' to the plates 17, 18, respectively. The left-hand end of the arms 24, 25, as viewed in the drawings, are joined by a bar 26 extending transversely of the bed B and having a threaded opening 27 adjacent the midpoint of its length which threadingly engages a threaded vertical shaft 28 having a handwheel 29 at its upper end. The shaft 28 is supported for rotation by .the bed B and, upon rotation of the shaft by the hand- .Y 36 which threadingly engages an internally threaded opening 37 in a bar 38 supported between the right-hand ends of the arms 33, 34, as the latter are viewed in Fig. 2. The structure of the arms 33, 34 differs somewhat from that of the arms 24, 25 for the matter of convenience in locating the parts, both sets of arms functioning in the same way to raise and lower the clamp plates 21, 22.

In accordance with the present invention, the load supports 11, 11 are constructed so that the beam 12, when supported thereby, is capable of pitching or yawing movements, or movement along a horizontal plane or vertical plane, or rotation about a horizontal axis, or a combination of all of the above-mentioned movements. Basically, the construction of the supports 11 or 11' is the same although each have somewhat different mechanism for clamping the beam 12. Therefore, only the load support 11 will be described in detail, it being understood that the basic structure and operation of the load support 11' is the same as that of the load support 11, and the basic structure of both supports being shown in the simplified drawing of Fig. 9.

The load support 11 comprises a horizontal base member 40 extending parallel to the length of the bed B and having legs 41, 42 depending from the opposite ends thereof. The base member 40 is supported by a rod 43 which extends parallel to the length of the bed B and extends through aligned apertures in the legs 41, 42. The rod 43 extends outwardly of the legs of the base member 40 with the opposite end portions of the rod being received in vertical slots 44 in transverse frame members 45, 46 extending between the plates 17, 18 at the opposite ends, respectively, of the rod 43. The construction is such that the base member 40 may rock about the axis of rod 43.

The base member 40 is normally urged to a position where the rod 43 abuts the upper ends of the slots 44 by a pair of horizontal springs 47 adjacent the outer side of plate 17, and a pair of horizontal springs 48 adjacent the outer side of the plate 18. The springs 47, 48 are each operatively connected to the base member 40 through a respective toggle linkage each of which comprises a pair of links 50, 51 which lie generally vertically when the base member is in its uppermost position shown in Figs. 3 and 9. The links 50 are operatively connected at their upper ends, as viewed in Fig. 2, to the opposite end portions of a transverse shaft 52 carried by the base member 40, and at their lower ends to the upper end of their respective links 51, the lower ends of the links 51, as viewed in Fig. 2, being pivotally connected to the opposite end portions of a transverse shaft 53 on the bed B. The shafts 52, 53 are in approximate vertical alignment in the illustrated embodiment.

As is best shown in Fig. 5, the lower link 51 of each of the toggle linkages is pivotally connected to the shaft 53 by a universal ball-type connection which comprises a bearing member 54 fixed to the shaft 53, the bearing member 54 having a generally truncated spherical configuration. The lower end of each link 51 is threaded into a respective socket member 55 having an eye 56 provided with an internal concave bearing surface adapted to mate with the surface of the corresponding bearing member 54. The bearing members 54 permit the socket members 55 and the links 51 to be rotated about the axis of the shaft 53 and will permit limited universal movement of the socket members 55 and links 51 in other angular directions.

The upper end of each of the lower links 51 is bifurcated to provide spaced portions 58 between which the lower end of the corresponding upper link 50 of the toggle linkage is positioned. Each link 50 and the portions 58 of its corresponding link 51 have aligned apertures for the reception of a bearing sleeve 60 for pivotally connecting the links to form the knee of the toggle linkage.

The upper end of each of the links 50 of the toggle linkages is received in an internally threaded socket memher 61 having an eye therein provided with a concave bearing surface 62 which cooperates with a ball-type bearing member 63 fixed to. the adjacent end of the shaft 52. The socket members 61 and the ball-type bearing members 63 provide universal ball-type connections for the links 50 similar to the, connection formed by the bearing members 54 and the socket members 55 and permit free relative rotational or rocking movement of the upper links 50 and the base member 40 about the axis of the shaft 52 as well as limited universal movement of the links 50 in other angular directions. The pitching movement about the shaft 52 is limited by the spacing between the. legs 41,, 42: and the frame members 45., 46.

A bolt 66 is positioned in each bearing sleeve 60 and a pair of plates 67, 68, positioned on opposite sides of the upper end of each link 51, are connected together by the bolt and its cooperating nut. The plates 67, 68 form connecting members to connect the springs to the toggle linkages. As viewed in Fig. 3 of the drawings, the plates 67, 68 extend to the right of the knee of the particular toggle linkage and the corresponding springs have one end connected to, the plates 67, 68 of the corresponding toggle linkage. The connections of the springs 48 to the plates 67, 68 01 the left-hand side of the bed B as viewed in Fig. 5 are best shown in Fig. 5 A pair ofbolts 69 extend between the plates 67", 68 to which the springs 48 are connected and the, springs 48 each have one end looping a different bolt 69, the bolts each having a sleeve 71 thereon which passes through the plates and provides a bearing surface for the ends of the, springs. Lateral movement of each of the ends of the springs 48 along the bolts" 69 and sleeves 71 is prevented by bushings 72 on each sleeve 71 and on opposite sides of the end of the respective springs 48. The springs 47 are connected to their corresponding plates 67, 68 in the same manner as the springs 48. The other ends of each pair of springs 47, 48 are connected to respective anchor plates 73 pivotally connected to the plates 17, 18 for movement about an axis extending transversely of the bed B.

The springs 47, 48 operate through the toggle linkages to bias the base member 40 upwardly to a position where the rod 43 engages the upper ends of the vertical slots 44 in the transverse frame members 45, 46. The springs will yieldably oppose downward vertical movement of the base member including the vertical component of the rocking or rolling movement of the base member 40 about the axis of the rod 43, the universal pivotal connections of the. toggle linkages to the base member 49 and to. the bed B being such as to not interfere with the desired limited rocking movement. The springs will also permit rocking or pitching movement of the base member 40 about the axis of shaft 52.

A pair of generally horizontal arms 75 are provided for guiding the movements of the base member. The arms 75 are located on the outer sides of the plates 17, 18 and are connected to the adjacent end of the shaft 52, respectively, outwardly of the connection of the adjacent upper link 50 to the. shaft. The pivotal connection of the arms 75 to the shaft 52 is the same as the pivotal connections of the links 50, 51 to the shafts 52, 53, respectively, and, therefore will not be again described. Sufiice it to say, however, that the connection permits rotation of the arms 75 about the axis of the shaft 52 and limited universal movement in other angular directions so as to permit limited rocking movement ofthe hase member 40, about the axis of the rod 43. The end of each arm 75 remote from the pivotal connections to the shaft 52 is connected to a respective link 77 which is generally vertical when the base member 40 is in its uppermost position shown in Fig. 2. The arms 75' are connected to the. upper ends of the links 77 and the lower ends of the links are, in turn, pivotally connected to the adjacent one of the plates 17, 18. The arms 75 are also each pivotally connected at a point intermediate its ends to one end of a respective link 78' having its other end pivoted to the adjacent one of the plates 17, '18. When the base member 40 is in its uppermost position, as shown in Fig. 3, the links 78 extend to the left from their pivotal connections to the plates 17, 18 and define acute angles with the horizontal.

The base member 40 has a load-engaging member 80 mounted thereon for horizontal movement transversely of the bed B. The load-engaging member 80 is secured to the base member 40 by a plurality of bolts 81 each of which passes through a respective elongated opening 82 in the base member 40 and threads into a respective aperture 83 in the load-engaging member. The elongated openings 82 extend in a direction transversely of the rod 43 and the bed B and permit shifting of the load-engaging member with respect to the base member 40 along a line extending transversely of the rod 43.

The load support 11, in the illustrated embodiment, is provided with means for securing thereto a load member which has a depending inverted U-shaped bracket 84 welded thereto with the lower ends of the legs of the bracket being turned inwardly toward each other to form horizontal lug portions 85, as is best shown in Fig. 5. When the load is positioned on the load support 11, the horizontal lug portions abut against the left-hand side of a block 86, as the latter is viewed in Fig. 3, welded to, and extending transversely of, the load-engaging member 80. A slide or latching plate 87 is operable to secure the beam 12 on the member 80 and is movably supported on the load-engaging member 80 for movement longitudinally of the bed B by spaced parallel rail portions 88 on the top of the member 80 and is adapted to pass between the legs of the U-shaped bracket 84 and over the lug portions 85 to prevent the lifting of the load member from the load support 11. The slide plate 87 is connected to the load-engaging member 80 by a pair of bolts 89 which pass through respective elongated openings 89a in the slide plate and thread into the loadengaging member 80.

The slide plate 87 has, as viewed in Figs. 2 and 7, a right-hand portion 90 of reduced width which extends through the block 86 to the right-hand side thereof. The right-hand end of the portion 90 has a block 91 fixed thereto which is engaged by the lower end of a lever 92 dependently supported from an L-shaped support arm 93 extending first upwardly from, and then to the right of, the block 86. The lever 92 is pivoted to the support arm 93 and is biased, by a spring 95, into engagement with the left-hand side of the block 91, as the latter is viewed in Figs. 2 and 7, to urge the slide plate 87 toward the right, the spring 95 being connected between the lever 92 and a post 96 fixed to the right-hand end portion of the load-engaging member 80. When the slide plate 87 is in its extreme right-hand or locking position, the bolts 88 are positioned adjacent to the left-hand end of slots 89, and the shoulder formed at the point where the slide plate 87 changes in width abuts the block 86 outwardly of the opening therein for passing the portion 90 of the slide plate.

The slide plate 87 is movable to the left, as viewed in Fig. 2, Le, to a releasing position, by the operation of a toggle linkage 99 comprised of a link 100 pivotally connected to the right-hand end of the reduced portion 90 of slide plate 87, and a link 101 pivotally connected to the post 95, the links 100, 101 being pivotally connected at their adjacent ends to form the knee of the toggle linkage.

The toggle linkage 99 is broken when the slide plate 87 is in its locking position and, when the linkage is moved toward a straight line position, it causes the slide plate 87 to move toward the left, as viewed in Fig. 2. The slide plate 87 is moved to its releasing position by means of a cable 103 having one end connected to the knee of the toggle linkage 99. The cable 103 extends downwardly from the toggle linkage 99 through the loadsupporting member 80 and the base member 40 and plate 17 and lying in a vertical plane and runs from the pulley 104 to a pulley 105 inclined at an angle with respect to the vertical and rotatably supported by a bifurcated arm 106 which is supported for movement about a horizontal axis by a post 107 extending horizontally inwardly from the inner side of the plate 17.

From the pulley 105, the cable 103 runs to the right along the bed B, as viewed in Fig. 2, and passes about a pulley 108 rotatably supported by the plate 17, and from the pulley 108 extends upwardly and about a directionchanging pulley 109 supported by the transverse frame member 46 at a point above the upper end of the slot 44 therein. The cable 103 passes around the pulley 109 and the end of the cable is tied to the rod 43. The abovedescribed pulley arrangement maintains tautness in the cable 103 as the base member 40 is depressed since the distance between the pulley 109 and the rod 43 increases the same amount that the distance between the knee of the toggle linkage 99 and the pulley 104 decreases upon depression of the base member 40.

The cable 103 is pulled downwardly to release the slide plate by moving the pulley 105 clockwise about its supporting post 107. To this end, a release cable 110 is connected at one end to the arm 106, and at the other end to one end of a release lever 111 pivotally mounted intermediate its ends on the bed B.

While the load on the load support 11 is being transported, it is desirable that the load support be locked against movement with respect to the bed B. To prevent horizontal movement of the load-engaging member 80 with respect to the base member 40, a latching member 115 is supported on the shaft 52 and is movable about the axis of the shaft from a position below the upper side of the base member 40 through an opening in the base member to a position where the member extends upwardly through the base member 40 into a recess 116 in the load-engaging member 80. The recess 116 is of substantially the same width as the latching member 115 and, therefore, prevents lateral horizontal movement of the load-engaging member 80 with respect to the base member 40 when the latching member 115 is engaged. A cable 117 is connected to a portion 118 of the latching member 115, which portion extends to the left of the shaft 52, as viewed in Fig. 8, and 'the latching member may be moved to a released position against the action of a biasing spring 120 by pulling on the cable 117. The biasing spring 120 is connected between a bracket 121 depending from the underside of the base member 40 and a U-shaped bracket 122 pivotally connected to the latching member 115 on the side of shaft 52 remote from the spring and is so arranged that it moves over center as the latching member 115 moves from its released position to its engaged position, or vice versa. The spring 120 will, therefore, tend to hold the latching member 115 in its released or engaged position.

The cable 117 is connected to a rocker member 124 pivotally connected to the plate 18 adjacent the inner side thereof. The rocker member 124, as is best shown in Fig. 5, has a first arm 125 to which the cable 117 is connected, and a second arm, angularly related to the first arm, to which a draw rod 126 is connected. The rocker member 124 is, by operation of the rod 126, movable about its axis to pull the cable 117 downwardly and release the latching member 115. The rod 126 extends from the rocker member 124 to the left along the bed B, as viewed in Fig. 2, and is pivotally connected to the lower end of a lever 127 which extends generally vertically and is pivoted intermediate its ends to the plate 18. A cable 128 is connected to the upper end of the lever 127 and to the same end of release lever 111 as the cable 103 so that the latching member 115 is simultaneously released upon the operation of cable 103 to operate the toggle 99.

The vertical and rocking movements of the base member 40 may be prevented in the illustrated load-supporting device by positioning a pair of pins 130, 131 under the leg 41 of the base member 40. The pins 130, 131 are slidably supported for axial movement by a bearing member 132 fixed to the transverse frame member 45, the bearing supporting the pins on opposite sides of the slot 44 for movement parallel to the length of the bed B. When the base member 40 is in its uppermost position the pins 133, 131 may be moved axially from an inactive position clear of the path of movement of the base member 40 to an active position shown in the drawings where the pins engage the lower end of the leg 41 and prevent the base member 45) from moving vertically or rocking about the rod 43. The pins 130, 131 extend to the left from the frame member 45 as viewed in the drawings, and have their left-hand ends connected together by a transverse bar 133. A rod 134 is pivotally connected to the transverse bar 133 and to the upper end of the lever 127 so that when the lever 127 is operated to release load-holding means the rod 134 operated to pull the pins 130, 131 to a position clear of the leg 41 of the base member 40 to permit vertical and rocking movements of the base member.

When the pins 130, 131 are moved to their outward or left-hand position to clear the pins of the base member 40, a catch member 135 moves to a position in engagement with the right-hand or inner side of the transverse bar 133, as the latter is viewed in Fig. 2, to prevent inward movement of the pins to their active position. As is best shown in Figs. 2 and 4, the catch member 135 is pivoted to the lower ends of spaced arms 136 which depend from the bearing member 132. The catch member 135 extends upwardly from its pivotal connection to the arms 136 and a spring 137 biases the catch member toward the bearing member 132. When the pins 130, 131 are in their active position as shown in Fig. 2 the upper right-hand corner of the catch member engages the left-hand side of the transverse bar 133, the corner being cut away as indicated in the drawings, and yieldably opposes movement of the pins from their active position. When the pins are pulled to the left, as viewed in Fig. 2, to move them to their inactive position, the catch member 135 will move downwardly against the action of the spring 137 and the transverse bar 133 will ride along the upper side of the catch member 135, and when the pins have been moved to their inactive position, the transverse member 132 will engage a cam portion 138 formed on the left-hand corner of the catch 134, as the latter is viewed in the drawings, which cam surface prevents the pins from moving inwardly toward their active position. When the pins 134?, 131 are to be moved to their active position, the pins are moved slightly to the left to relieve the pressure on the catch member 135 and the latter is moved downwardly to permit inward movement of the transverse bar 133 and the pins 130, 131.

The load support 11 is preferably constructed in a manner similar to the load support 11 so that it will yield in the same directions as the load support 11. To this end, the load support 11 includes a base member 40 supported for rocking movement on a rod 43' which is, in turn, supported on the bed B for vertical linear movement in the same manner as the rod 43. The vertical linear movement and the rocking movement of the base member 40 is opposed by springs on the opposite sides of the bed B connected to the base member 40 by respective toggle linkages with only the springs 41 and toggle linkage on one side of the bed appearing in the drawing. The springs 47' are connected to the base member 40' through its respective toggle linkage comprising links 56, 51' pivotally connected to the base member 40' and the bed B, respectively, and to each other at their adjacent ends to form the knee of the toggle linkage. As in the load support 11, the springs 47 are connected to the knee of the toggle linkage formed by the links 50, 51. The connections of the toggle linkages to the base member 40 are such to permit rocking movement of the member about an axis extending transversely of the rod 43'. The movements of the base member 40' are guided by arms 75', only one of which appears in the drawings, which are supported and which operate similar to the arms 75.

The base member 40 is provided with a load-engaging member supported on the base member for horizontal linear movement with respect thereto, preferably along a line extending transversely of the axis of the rod 43. The load-engaging member 80'- is provided with load-holding means which may be of any suitable type and, if desired, may be similar to that of the load support 11. The load-holding means 150 is preferably releasable through the operation of a cable 151 connected to the release lever 111 at the end thereof opposite the operative connection of cables 103 and 134. A release cable 153 for releasing a mechanism which may be of the same construction as the corresponding mechanism of the load support 11, for holding the base member 40 against vertical, linear and rocking movement, is connected to the same end of the release lever 111 as the cable 151. When the release lever 111 is moved clockwise about its pivot, both of the load supports 11, 11 are released for movement in their various directions. Preferably, a release cable 155 for the collapsible support 10 is also operatively connected to the release lever 111 so that the support 10 is collapsed simultaneously with the release of the load supports 11, 11.

The bed B is shown in the drawing as being comprised of two separate sections 156, 157, for supporting the load supports 11, 11, respectively, which sections are connectable together to form the complete bed or base. Preferably, the collapsible support 10 is supported on a separate section 158 which is also detachably connected to the section 157. By constructing the load-supporting device in this manner, the load supports 11, 11' may be used individually if so desired, or may be combined as illustrated in the drawing for providing two spaced supports which are yieldable in a plurality of directions. Preferably, the bed B is provided with foot members 160 which are pivotally supported on opposite sides of the bed B for movement from a position along the sides of the bed to a position extending transversely of the bed, only one of the foot members 160 being shown in the drawings. When the foot members 160 are pivoted to a position extending transversely of the bed, they engage the supporting surface for the bed and stabilize the latter against tipping. Suitable cam means 161 is provided for locking the foot members in their active or inactive positions.

From the above description it can be seen that by applying a force in the proper direction and place, the beam 12 can be made to move vertically or horizontally, pitch, yaw, or along a resultant path having the above movements as components. Furthermore, it can be seen that the present invention provides a load-supporting device comprising a load support yieldable in a plurality of directions against biasing means operatively connected to the load support, preferably through a linkage, such as a toggle linkage, which decreases the mechanical advantage of the biasing means as the load support is depressed so that the force necessary to depress the load support against the biasing means does not increase in proportion to the increase in the biasing force as the load is depressed, and that a load support which is capable of yawing, pitching, and vertical and horizontal linear movement has also been provided.

While the preferred embodiment of the present invention has been described in considerable detail, further modifications, constructions and arrangements will appear to those skilled in the art, and it is hereby my intention to cover all such modifications, constructions and arrangements which fall within the spirit and scope of the appended claims.

. Having thus described my invention, I claim:

1. In a load-supporting device, a frame, a load-supporting member, means for supporting said load-supporting member on said frame for movement along a generally vertical line and for rocking movement about an axis angularly related to said vertical line of movement and contained in a common plane therewith, said axis moving vertically with said member, and means for urging said member upwardly along said line and for yieldably opposing movement about said axis including a collapsible linkage connected to said frame, a universal type connection connecting said linkage to said load supporting member at a point from said axis, and biasing means urging said linkage to an extended position, said linkage including a second universal type connection permitting relative movement between the portion of said linkage connected to said load supporting member by said first universal type connection and said frame. v

2. In a load-supporting device, a frame, a load-supporting member, means supporting said load-supporting member on said frame for movement along a generally vertical line and for rocking movement about an axis angularly related to said vertical line of movement and contained in a common plane therewith, said axis moving vertically with said member, a pair of collapsible linkages movable to an extended position for moving said member in one direction along said vertical line of movement, universal connections connecting said linkages to said load supporting member at spaced points spaced from said axis to support said load supporting member for tilting movement about an axis extending transversely of the first axis, and biasing means connected to said linkages for biasing said linkages to an extended position.

3. In a load-supporting device, a frame, a load-supporting member, means guiding and supporting said loadsupporting member on said frame for movement along a generally vertical line and for rocking movement about an axis angularly related to said vertical line cluding biasing means whose biasing force increases as said member is -moved against the action thereof, and a linkage for operatively connecting said biasing means to said member and effective to decrease the mechanical ad vantage of the biasing means operating through the linkage as said member is moved downwardly, said linkage including a first universal type connection connecting a portion of said linkage to said load supporting member,

at a point olfsetfrom said axis and a second universal type connection between said portion and said frame whereby said portion is capable of limited universal movement relative to said frame.

4. In a load-supporting device, a frame, a load-supporting member, means for guiding and supporting said loadsupporting member on said frame for movement along a generally vertical line and for rocking movement about an axis angularly related to said vertical line of movement and contained in a common plane therewith, a pair of toggle linkages each movable toward a straight line position to move said member upwardly, universal type pivotal connections connecting portions of said toggle linkages to said member at spaced points offset from said axis to support said member for tilting movement about a second axis extending transversely of the first mentioned axis, said linkages including second universal type connections between said portions and said frame and permitting limited universal movement of said portions relative to said frame, and biasing means operatively connected to said toggle linkages for urging said toggle linkages toward their straight line positions.

5. In a load-supporting device, a frame, a load-supporting member, means supporting said load-supporting member on said frame for movement along a generally vertical If) line and for rocking movement about an axis angularly related to said vertical line and contained in a common plane therewith, the last said means comprising a toggle linkage movable toward a straight line position to move said member upwardly, said toggle linkage being substantially parallel to said plane, connections respectively operatively connecting said toggle linkage to said member and to said frame and each comprising a universal type connection permitting at least limited angular movement in a plurality of directions, and biasing means operatively connected to said linkage for urging said linkage toward a straight line position.

6. In a load-supporting device, a frame, a load-supporting member, a toggle linkage, universal type pivotal connections respectively operatively connecting said toggle linkage to said frame and said load-supporting member to move said load-supporting member vertically upon movement of said toggle linkage toward a straight line position, each of said connections permitting limited universal movement of said linkage with respect to said loadsupporting member and frame in at least a plurality of directions,'means for guiding the vertical movement of said member and for permitting rotation of said member with respect to said toggle linkage about an axis extending in a direction perpendicularly related to the vertical movement of the member and permitting rocking movement of the load-supporting member about an axis perpendicular to the plane of said toggle linkage, and biasing means operative through said toggle linkage to bias said member in an upward direction and to oppose rocking movement thereof about said first axis.

7. In a load-supporting device, a frame, a first member, first and second toggle linkages on opposite sides of said member, universal type connections connecting one end of each of said toggle linkages to said member and the other end of each of said linkages to said frame, said toggle linkages being movable toward a straight line position to raise said member, spaced guide members at opposite ends of said first member, first and second rod-like members extending from the opposite ends of said first member and received respectively in vertically extending slots in said guide members, the thickness of said rod-like members being substantially equal to the width of said slot and said rod-like members and slots cooperating to permit vertical movement of said member and rocking movement about the axis of said rod-like members and pitching movement about an axis perpendicular to said rod-like members, biasing springs operatively connected to said toggle linkages and operative to urge the toggle linkages toward a straight line position, said springs being so proportioned that the force required to depress the first member an additional unit distance against the spring remains approximately the same throughout the range of Vertical movement of said first member, a second member supported on said first member for movement parallel to the plane of said first member and transversely of the axis of said rod-like members.

8. In a load supporting device, a supporting member, a frame including guide means constraining spaced portions of said member to move along parallel lines and said member being rockable about an axis through said portions, and means for supporting said member for rocking movement about a second axis perpendicular to the first-mentioned axis and for urging it in one direction along said lines comprising a pair of links, a universal type pivotal connection connecting one end of one of said links to said load supporting members, first and second pivotal connections connecting the ends of the other of said links to the other end of said one link and said frame respectively whereby said links form a toggle linkage, at least one of said first and second pivotal connections being a universal type connection, biasing means connected to said frame and to said toggle links and urging the toggle linkage formed by said links toward a straight line position to urge said supporting member in one direction along said lines and yieldable to permit the collapse of the toggle linkage.

9. In a load supporting device, a supporting member, a frame including means defining spaced slots for receiving spaced portions of said member to guide said portions along parallel lines of movement and to permit rocking and pitching of said member relative to said frame, and means for supporting said member and urging it in one direction along said lines comprising a pair of links, a universal type pivotal connection connecting one end of said links to said supporting member intermediate said slots, first and second pivotal connections connecting the ends of the other of said links to said frame and to the other end of said one link respectively, whereby said links form a toggle linkage, at least one of said first and second pivotal connections being a universal type connection, biasing means connected to said frame and to said links and urging the toggle linkage formed thereby toward a straight line position to urge said supporting member in one direction along said lines and yieldable to permit the collapse of the toggle linkage.

10. In a load supporting device, a supporting member, a frame including guide means constraining spaced portions of said member to move along parallel lines and said member being rockable about an axis through said portions, a load supporting member, guide means mounting said load supporting member on said supporting member for movement transversely of the rocking axis in response to an external force applied to the load-supporting memher, and means for supporting said member for rocking movement about a second axis perpendicular to the firstmentioned axis and for urging it in one direction along said lines comprising a pair of links, a universal type pivotal connection connecting one end of one of said links to said load supporting members, first and second pivotal connections connecting the ends of the other of said links to said frame and to the other end of said one link respectively, whereby said links form a toggle linkage, at least one of said first and second pivotal connections being a universal type connection, biasing means conected to said frame and to said toggle links and urging the toggle linkage formed by said links toward a straight line position to urge said supporting member in one direction along said lines and yieldable to permit the collapse of the toggle linkage.

11. In a load supporting device, a supporting member, a frame including means defining spaced slots for *receiving spaced portions of said member to guide said portions along parallel lines of movement and to permit rocking and pitching of said member relative to said frame, a load supporting member, guide means mounting said load supporting member on said supporting member for movement transversely of the rocking axis in response to an external force applied to the load-supporting member, and means for supporting said member and urging it in one direction along said lines comprising a pair of links, a universal type pivotal connection connecting one end of said links to said supporting member intermediate said slots, first and second pivotal connections connecting the ends of the other of said links to said frame and to the other of said one link respectively, whereby said links form a toggle linkage, at least one of said first and second pivotal connections being a universal type connection, biasing means connected to said frame and to said links and urging the toggle linkage formed thereby toward a straight line position to urge said supporting member in one direction along said lines and yieldable to permit the collapse of the toggle linkage.

12. A load handling apparatus adapted to support an elongated load for yawing and pitching movement and comprising first and second load supporting devices spaced from each other along a first line extending in a generally horizontal direction, said devices each comprising a frame, a supporting member, means mounting said supporting member on said frame for movement along a generally vertical line and for rocking movement about first and second axes extending in generally perpendicularly related directions, said first axis being angularly related to said vertical line of movement and contained in a common plane therewith, means for biasing said supporting member in an upward direction along said vertical line of movement and for yieldably opposing movement along said vertical line in the opposite direction, a load carrying member, and connecting means mounting said load carrying member on said supporting member for substantially free movement independently of said supporting member and in a direction extending transversely of said first axis in response to a pushing or pulling force applied thereto whereby the load carried by the load carrying member may be moved relative to said supporting member and transversely of said first axis by pushing or pulling thereon and enabling the load carried by said first and second devices to be yawed about an axis contained in a vertical plane perpendicular to said first line and disposed intermediate said devices.

References Cited in the file of this patent UNITED STATES PATENTS

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