US2170706A - Brick grab - Google Patents

Description

J. P. CALLAGHAN Aug. 22, 1939.

BRICK GRAB 3 Sheets-Sheet L y Filed Jan. 26 1938 lllllll l'l l l Q R2 n g] INVENTOR m LLJJL RNEYS .jzhnficallagham BY WW? ATTO 19394 J. P. CALLAGHAN I 2,170,706

mucx GRAB I Filed Jan. 26, 19 8 s Sheets-Sheet 2 Lyynmgssss j; P C l IZVENTOR 4 r o a 6 BY ATTORNEYS Aug. 22, 1939.

J. P. CALLAGHAN BRICK GRAB Filed Jan. 26,. 1938 5 Sheets-Sheet 3 SSES VYITNE INVENTOR JO/IHR CaZZaghan BY M W AITSlZNEYfi Patented Aug. 22, 1939 UNITED STATES PATENT OFFKIE BRICK GRAB Application January 26, 1938, Serial No. 186,971

Claims.

This invention relates to improvements in grabs or lifters and has particular relation to apparatus of the character to be used in lifting piles of bricks, stones and the like.

It is an object of the invention to provide an improved brick grab of simple, sturdy construction which will operate in an efiicient manner over a long period of time with comparative freedom from wear.

A further object of the invention is the provision of an improved grab of the above character having improved operating leverage and linkage between the gripping jaws and lifting head and also having improved guide mechanism and locking means whereby the jaws may be locked in open position.

For a fuller understanding of the invention reference should be had to the accompanying drawings in which Fig. 1 is a front elevation of a brick grab embodying my invention;

Fig. 2 is a side elevation of the brick grab;

Fig. 3 is a plan view;

Fig. 4 is a detailed view showing the construction of one of the grippingv buttons and of the lower end of the shield plate employed on the gripping jaws;

Fig. 5 is a rear view of one of the bell cranks used in the gripping jaws;

Fig. 6 is a side view of the bell crank; and

Fig. '7 is a plan view from the lower side thereof of the locking mechanismfor retaining the gripping jaws in open position.

My improved grab comprises a pair of jaws indicated generally at 8, for gripping a pile of bricks or other articles, and a lifting head indicated by the numeral 9 for lifting the grab and also for controlling the operation of the jaws. The gripping jaws are connected to the lifting head by a series of levers and links so as to provide for a high efiiciency in operation, and when the lifting head is shifted away from the jaws they are caused to close and grip the articles which are to be lifted, and likewise, when the lifting head is shifted towards the jaws they are caused to open and release the articles.

The grab is provided with a frame 10 which is generally rectangular in plan and on which the gripping jaws and. operating levers and linkage are mounted. The gripping jaws preferably comprise two pairs of confronting bell cranks II which are spaced apart as shown and pivotally mounted on the shafts I2 adjacent the four corners of the frame It. Each of the bell crank levers is formed. of a downwardly extending bifurcated arm 14 which serves as the gripping portion of the jaw, and also a horizontal arm l5 whereby the bell crank is pivoted to shift the jaws towards and away from each other.

The arms 15 are relatively long so as to provide for maximum leverage and extend from the pivotal points 2 to adjacent the opposite side of the frame as shown. To prevent interference between the arms 15 of the confronting bell cranks it will be appreciated that they must be arranged in staggered relation and for this purpose I prefer to form each of the bell cranks with a spacing collar it on one side around the piv otal point. In this way the bell cranks in each pair are spaced an equal distance apart but one of the pairs is offset with respect to the other, as most clearly shown in Fig. 3. It will be appreciated that relatively heavy loads are engaged and lifted by the gripping jaws and accordingly they should be of relatively strong construction, and for this purpose I prefer to form the downwardly depending arms M of the bell cranks of angle bars as shown. The lower, bifurcated ends of the arms in each pair of bell cranks are suitably connected together so as to form a unitary gripping jaw as by means of T-bars 16.

Usually the surface of a pile of bricks or similar articles is irregular, and also, it will be appreciated that in lifting a pile ofbricks as. a unit a maximum amount of gripping pressure must be applied to the lower rows of bricks upon which the superimposed bricks are supported. For this reason, adjacent the lower edge of the gripping jaws I provide confronting rows of yielding, inwardly projecting gripping buttons 18 positioned so that they will engage the lower row of a pile of bricks. or other articles. and formed so that they will compensate for any irregularities in the surface thereof, but nevertheless will apply sufficient gripping pressure so as to enable a relatively large and heavypile to be lifted by the grab. For this purpose I form channels adjacent the lower edges of the gripping jaws as by securing angle bars I! to the T-bars as shown, in spaced relation from the bottom thereof. The gripping buttons are positioned in the channels and each comprises a cap having depending ends 19 projecting into the channel and having sliding engagement with the horizontal portions of the T-bar and angle bar which accordingly serve as guides for the buttons. Each of the gripping buttons is held in position by a pin 28 secured in the cap and extending through and having loose engagement with the vertical portion of the T-bar IS. The outer end of each of the pins. 20

respective gripping jaws.

is provided with suitable means such as a cotter pin 2!, to prevent the button from escaping from the channel. To normally hold the button in extended position, spiral springs 22 are formed around the pins 20. It will be appreciated that since the grab is used to grip and lift articles of considerable weight the springs 22 must be relatively strong and must exert considerable force upon the gripping buttons to urge them into the extended position shown in Figs. 1 and 4. A continuous row of confronting buttons I8 is provided in each side of the gripping jaws.

I have found that it is desirable that the jaws should be provided with smooth inner and outer surfaces so as not to dislodge any of the bricks or similar articles that are to be lifted by the grab and for this purpose I encase each side of the jaw with shield plates 23 and 24. The shield plates 23, which cover the outer surfaces of the jaws may be shaped to conform with the general contour of the depending arms M as shown most clearly in Fig. 2, and they are preferably rigidly secured in position as by means of angle bars 25 and brackets 26.

The shield plates 24 on the inner faces of the gripping jaws are yieldingly held in position so that normally the lower ends thereof are spaced from their respective jaws so that they will shift towards the jaws when pressure is applied thereto. Thus, at their upper ends the plates 23 are connected by means of flexible strips 21 to brackets 28 thereby permitting the lower portion of the shield plates to shift relative to the jaws. Adjacent their lower ends they are connected to pins 29 which extend through the depending arms I4 and have sliding engagement therewith so that the lower portions may shift towards and away from the arms. Suitable means such as the nuts 30 are provided at the ends of the screws 29 so as to limit the outward movement of the shield plates, and spiral springs 3| are disposed around the pins so as to normally hold the shield plates 23 in spaced relation with regard to their Due to the fact that the lower ends of the shield plates 23 are held in positon by a relatively few number of pins 29 the combined resistance of the springs 3| is not as great as the combined resistance of the springs 22 which are disposed in the gripping buttons I8. As a result of this structure, when the gripping jaws engage a pile of bricks or similar articles the shield plates 23 will yield and the burden of gripping the pile of bricks rests primarily upon the gripping buttons l8.

The operation of the gripping jaws is caused by shifting the arms l up and down so as to cause the arms M to shift towards and away from each other. The shifting of the arms i5 is controlled by a series of links and levers which are connected to the lifting head as shown. Thus, each of the arms I5 is pivotally connected adjacent its end to a link 33 which in turn is pivoted to a link 34 pivotally secured to a bracket 35. It will be seen that the links 33 and 34 correspond in number to the number of bell crank levers employed. Thus, in the present instance four bell crank levers are employed and accordingly, four of each of the links 33 and 34 are likewise employed. Each of the links 34 should preferably be positioned above the arm E5 to which it is connected at least at the point of connection but at their inner ends they are preferably offset towards each other so as to facilitate connection to the head as shown in Fig. 3. The brackets 35 are pivotally mounted at the four tures 5i and 52.

corners of the frame l0, adjacent to the shafts l2 as shown.

So as to obtain the maximum leverage the intermediate links 33 should preferably be pivoted to the links 34 adjacent the brackets 35 while the free ends of the links 34 are pivotally connected to links 38 which are pivoted to the two ends of the lifting head 9. The brackets 35 are free to pivot towards and away from one another so as to permit the links 34 to freely pivot from lowered to raised position. Adjacent the center of the lifting head a bail or loop 40 may be provided whereby the grab may be suitably suspended.

A satisfactory lifting head is shown in the drawings and comprises a beam formed of a pair of spaced parallel plates 4| having an interconnecting fin 42 adjacent the central portion thereof and a pair of cross rods or pins 43 adjacent the two ends thereof to which the links 38 are connected.

Due to the linkage and levers hereinbefore described, when the bail 40 is raised upwardly the arms l4 will shift towards each other thereby closing the gripping jaws 8. This is due tothe fact that the lifting head raises the links 39, which in turn pivot the inner ends of the links 34 upwardly. The pivoting of links 34 upwardly through the movement of links 33 causes the arms l5 to pivot upwardly, with the result that the depending arms [4 pivot towards each other. When the bail 40 is lowered to the position shown in. the drawings, the opposite action to that just described takes place, with the result that the arms l4 shift away from each other and the grip ping jaws 8 are in open position.

So as to insure a uniform and equal action of the several links I provide a guide which causes the beam to move up and down in a predetermined manner. This guide takes the form of a tube. 44 which is secured adjacent its lower end to the frame i0, and a shaft 45 positioned in the tube so as to slide telescopically therein and connected at its upper end as by means of a pin 46 to the lifting head. Thus, as the beam moves towards and away from the frame its movement is guided by the shifting of shaft 45 in the tube 44. To prevent jamming and so as to obtain more eflicient operation the tube 44 and shaft 45 are positioned in approximately the center of gravity of the grab beneath the bail 46.

At times it is desirable to lock the jaws in open position so that the device may be lowered over the pile of bricks as shown in Fig. 1 without the jaws closing, and for this purpose I provide improved locking mechanism which is shown most clearly in Figs. 2 and 7. This locking mechanism consists of an inverted channel bar 48 suitably secured between two sides of the frame of the grab. Adjacent the central portion of the channel bar a plate 49 is provided having a relatively enlarged opening 50 fitted around the tube 44 so as to permit the plate 49 to shift longitudinally relative to the tube 44.

The tube 44 is provided with a pair of aligned apertures 5| on opposite sides thereof adjacent the channel 48 and the shaft 45 is likewise formed with an aperture 52 extending therethrough which is in alignment with the apertures 5| in the tube when the beam is in lowered position and the jaws are opened as shown in Figs. 1 and 2. So as to lock the jaws in this position I provide suitable means such as a pin which may be shifted so as to extend through the aper- This mechanism comprises a pair of rods 53 and 54 extending in opposite directions from the plate 49 through the channel 48. Each of the rods has an operating handle 55 at the outer end thereof which are positioned on opposite sides of the grab whereby the jaws may be locked in open position from either side of the grab. The rods are supported in the channel by brackets 55. Each of the rods is likewise secured to the plate 49 as by means of the pins At its inner end the rod 54 is provided with an enlarged portion 58 extending partially across the opening 563 in plate 49 and in alignment with the aperture 5| in tube 44. By shifting either of the handles 55 to the left as viewed in Figs. 2 and '7 the member 58 can be extended through the aligned apertures 5| and 52 to lock the jaws in open position. To release the jaws the handles 55 are shifted to the right as viewed in these figures of the drawings. As a convenience and to aid in guiding the jaws as they are being lowered over the articles to be shifted handles 66 are connected to the depending arms l4 so as to project outwardly beyond the shield plates 23.

In using the brick grab the jaws are locked in open position by projecting the member 58 through the apertures 5| and 52 as heretofore described. The jaws are then lowered over the article or articles to be lifted, such as the pile of bricks indicated in dotted lines at Bl in Fig. 1. Due to the shield plates 23 and 24 it will be appreciated that there are no projecting surfaces to engage or dislodge the bricks as the jaws are being lowered, both inner and outer faces of' the jaws presenting smooth, even surfaces. When the jaws have thus been lowered, the locking mechanism is released by shifting one of the handles 55 to the right. The bail 40 is then lifted upwardly. The first result of lifting the bail upwardly is to close the jaws, due to the fact that the lifting head 9, levers 34, links 33 and arms l5 are all shifted or pivoted upwardly, causing the arms I 4 to pivot inwardly towards each other.

Due to the arrangement of the levers and links as heretofore described a maximum amount of leverage is obtained with the result that the jaws exert considerable pressure against the pile of bricks or other articles being lifted. The gripping buttons [8 engage and firmly grip the lower row of bricks and exert sufficient pressure so that the entire pile of bricks may be supported in this manner. The continued raising of the bail 4!) thereafter causes the brick grab together with the pile of bricks or other articles gripped between the jaws to be raised upwardly. The grab can thus be shifted to the desired position, where it is lowered. After the pile of bricks and the grab rest upon the ground, continued lowering of the bail results in opening of the jaws to the position shown in Fig. 1. The jaws can then be locked in open position and the grab is again ready to be operated in the manner above described.

It will be appreciated that I have provided an improved brick grab of simple, sturdy construction, which is efficient in operation and which may be used over a long period of time with comparative freedom from wear. It should be understood that while the device has been referred to as a brick grab it may be used for gripping and lifting other articles, and this name should not be interpreted as restricting the grab to this particular use. It should also be understood that modifications may be made in the illustrated embodiment of the invention without departing from the invention as set forth in the accompanying claims.

I claim:

1. A brick grab comprising a frame, gripping jaws pivotally supported by the frame, a lifting head for supporting the grab, means connected between the lifting head and gripping jaws whereby shifting of the head towards the jaws causes them to open and shifting of the head away from the jaws causes them to close, guide means comprising a tube supported by the frame, and a shaft supported by the lifting head and disposed in and shiftable relative to the tube, said tube and shaft having apertures therein which are in registry when the head is in lowered position and the jaws are open, a channel member disposed transversely of the frame adjacent the lower portion of the tube, a plate positioned in the channel member and having an opening to receive the tube, said opening being relatively elongated so that the plate can shift longitudinally with respect to the tube, a pair of rods secured to the plate and extending through the channel member whereby the plate may be shifted, and a locking pin extending a portion of the distance across the opening in the plate and positioned so that it may be projected through the apertures in the tube and shaft when they are in registry so as to lock the jaws in open position.

2. A brick grab as specified in claim 1 in which the locking pin is integral with one of the rods secured to the plate.

3. A brick grab as specified in claim 1 in which the rods extend in opposite directions to opposite sides of the frame and have operating handles formed at the ends thereof.

4. A brick grab comprising a frame, gripping jaws comprising a pair of confronting bell cranks pivoted to opposite sides of the frame, said bell cranks having downwardly depending gripping arms and horizontal operating arms extending substantially across the frame, a lifting head, and means connecting the lifting head and bell cranks whereby shifting of the head towards the frame opens the jaws and shifting of the head away from the frame closes the jaws, said means comprising a pair of brackets pivotally mounted on opposite sides of the frame, a pair of levers pivoted to the brackets and extending to adjacent the center of the frame, a link pivotally connected between the inner ends of the levers and the lifting head, and links connected between the ends of the operating arms of the bell cranks and the said levers adjacent the points of connection with the brackets.

5. A brick grab as specified in claim 4 in which interengaging guide means are supported on the frame and lifting head adjacent the approximate center of gravity of the brick grab.

JOHN P. CALLAGHAN.

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