US2178792A

US2178792A - Shore jack

Info

Publication number: US2178792A
Application number: US40717A
Authority: US
Inventors: Lawrence S Holmboe
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-09-16
Filing date: 1935-09-16
Publication date: 1939-11-07
Anticipated expiration: 1956-11-07

Description

Nov. 7, 1939. L, s HQLMBOE 2,178,792

- SHORE JACK Filed Sept. 16, 1935 INVENTOR ATTORNEY Patented Nov. 7, 1939 UNITEDSTATES caramorp g- Lawrence S. Holmboe, Oklahoma City, Okla. Application September 16, 1935, Serial No. 10,717

3 Claims.

My invention relates to an improvement in shore jacks, and more particularly to shore jacks for use in shoring, bracing, jacking and scaffolding, as used ordinarily in general construction work. 1

It is particularly adapted for use in connection with my device for shoring, jacking and scaffolding either under tension or compression, and as shown in my Patent No. 1,932,072 issued October 24, 1933, but it is distinctly understood I am not limiting it to such use. It can be used as well in connection with buildings and reinforced concrete structures of all kinds, in connection with mines, in connection with braces for sewers and other trenches, in connection with braces for caving excavations, in connection with scaffolds and hoist towers, and in connection with like uses where such a member is desired.

The primary object is to produce a jacking device of the character described which may be handled and used by one hand of the operator, leaving the other hand free to handle the shoring, and the like.

Other objects are to produce a device of the character described which will be new, novel, practical and of utility; which will securely hold in place the parts on which it is used; which will not scar, mar, or weaken, the material on which it is being used; the frame of which will have one open side for permitting it to be easily placed in position for use and to be changed without re-' moving the frame; which has few parts; which can be easily handled, applied and used; which may be easily removed for further use; which can be used in tension work as well as in compres-- sion work; which permits the load to be carried on its frame rather than on its friction plates; which will permit the frame to be free to pivot thus preventing to any appreciable extent either of the plates from eating into the wood, or material upon which it is used; and, which will be efficient in accomplishing all of the purposes for which it is intended.

The devices inuse at the present time for jack- (or. 254-120 g to be easily applied to the members upon which it is to be used, and permitting it to be easily operated with one hand, leaving the other hand free for other" uses. It-can be operated by one man, and can be removed by one man.

With these and other objects in view as will more fully appear hereinbelow, my invention consists in the construction, novel features, and combination of parts hereinafter more fully described, pointed out in the claims hereto appended, and illustrated in the accompanying one-sheet drawing, of which,

Figure 1 is a perspective view of the device showing the actuating lever in a plurality of posi-; tions, and also showing the clamping members in a plurality of positions;

Figure 2 is a plan view of the device; and,

. Figure 3 is a side elevational view of two shore members connected by a combination clamp and bearing structure, their upper ends broken away, with my device installed on the lower one and in lifting position with relation to the upper one,

Like characters of reference designate like parts in all the figures.

It is understood that various changes in the form, proportion, size, shape, weight and other details of construction, within the scope-of my of which, for the purpose of illustrating the invention, is shown in theaccompanying drawing whereinp- The numeral l designates the lower one of two shore members and 2 designates the upper one, both fitting together and adapted to slide longitudinally with relation to each other; the

lowerone preferably having notches, one of which notches is shown at 3; d designates one of the clamping members or collars (the second one which is similar in structure and which is ordi-- narily disposed in a similar manner some distance above the first, not being shown), having; bearing plates 5. None of the above described members are claimed as a part of my invention per se.

The jacking device consists essentially of a one piece U-shaped pivoting collar designated as a whole by 6 having a base or body! with perpendicularly outstanding arms or legs 8 and 9, said arms being provided with pivot pins It for holding in connection with cotter-keys II adjustable jacking clamps or gripping plates l2 and I3. Clamps or plates l2 and I3 are pivotally attached to the pivot pins I 0 on said arms 8 and 9 and preferably held thereon by the cotter-keys II. The frame is provided with lugs or projections so positioned that when the frame is horizontal the faces of the pivoting plates l2 and I3 are not allowed to deviate far from the vertical, thereby making it easy to slip the jack on the shore with the use of only one hand. Said plates are movable or automatically adjustable so as to be easily positioned on one of the shore members, and on their inner faces I4 are preferably kerfed, as shown at l5 but not toothed, so as to give a gripping effect without eating into the Wood or material to be gripped. The manner in which said clamps or plates l2 and [3 are movable or automatically adjustable is best shown in Fig. l at "5-46 and I1l1, and l8-- 8 and 59-49. On oneof the arms of said collar 6, preferably arm 9 (though this may be on either arm) is an upstanding boss 20 having a perpendicularly extending pivot pin 25. Pivotally attached on said pin 2| by a cotter-key 22 is a lever Said lever 23 has a hub 24 as best shown in Fig, I. Said lever has an eccentric head 25 having an approximately flat portion 26 and a bulged or enlarged portion 21, the outer edge of said portion 26 and said portion 21 at right angle to the handle of said lever 23 presents a transversely fiat-surface 28 as best shown in Fig. 2, for contacting the end of one of said shore members as best shown at 29 in Fig. 3.

Operation The jacking member is placed with its open end slipped .over the strut or lower shore member I and the remainder of said jacking member surrounding three sides of said member I as shown in Fig. 3 with the lever 23 in the downward or dotted line position as shown in the lower portion of Fig. l, the jacking clamps or gripping plates l2 and I3 at the left are pushed up on member I as far as possible, after which lever 23 is raised to the solid line position as shown in order to raise the strut or upper shore member 2; It is preferred that gripping plate l2 be positioned somewhat higher than the corresponding plate l3 at the right, thus putting the U-shaped bracket 6 in a preferred position to carry the load when jacking lever 23 is operated.

The above described operation applies when the device is used as a compression load in which instance the bearing plate 5 contacting the shore member 2 will be lower than said plate 5 on member I. If it is desired for use of the device as a tension load said relatively disposed ends of said plate or collar 5 will be reversed.

The assembled shore as shown in Fig. 3, butin collapsed position, is taken to the place where erection is desired and placed .on the floor in a vertical position. The clamp assemblies are loosened by tapping on the underneath side of the lowermost members 5. Shore member 2 is then slid upwardly until its top contacts with the ceiling or forms above. The clamp assemblies automatically clamp it and hold it in this position. By inclining the shore slightly before contact and then drawing it to its vertical position, any slight play is taken up and the jacking assembly 8-l2-|3--23, does not have to be used to get the shore fairly tight. However, if it is desired to get the shore very tight, the jacking assembly is attached to shore member I in the position shown in Fig. 3. This can be accomplished with the use of but one hand, because of the arrangement of the assembly which holds the clamping plates l2 and I3 in a vertical position. Handle 23 is then lifted (a pipe extension being used on the handle if greater force is required) and the eccentric surface 21- at the end of the lever 23 exerts a pressure on the bottom of shore member 2.

Loads up to three thousand pounds per shore may be easily lifted by this means. To lift heavier loads, it is only necessary to use additional shores. After the load has been lifted, it may be held in position without appreciable settlement after removal of the lifting assembly by tapping the lowermost clamping plate 5 on top with a hammer before the jacking assembly is removed. After the shores are jacked up and finally adjusted in place, safety nails may be driven. To loosen the shore it is only necessary to remove these safety nails and tap the two lowermost clamps on their surfaces.

Obviously, the invention is susceptible .of embodiment in forms other than that which is illustrated in the accompanying drawing and described herein, and applicable for uses and purposes other than as detailed, and I therefore consider as my own all such modifications and adaptations and other uses of the form .of the device herein described as fairly fall within the scope of my invention.

Having thus described myinvention, what is claimed and desired to be secured by Letters Patent, is: V

1. In a shoring jacka rigid U shaped frame adapted to embrace a shore member, substantially flat gripping plates pivoted to the arms of the U frame and adapted to grip the shore member,

andload-lifting means supported by the frame adjacent to one of the arms of the U frame tending to tilt the frame and gripping plates.

2. In a shoring jack a rigid U shaped frame adapted to embrace a shore member, substantially flat gripping plates pivoted to the arms of the U frame and adapted to grip the shore member, and load-lifting means supported by'the frame adjacent to one of the arms of the U frame tending to tilt the frame and gripping plates, and including a cam lever pivotally attached to the U shaped frame.

3. In'a shoring jack a rigid U shaped frame adapted to embrace a shore member, substantially fiat gripping plates pivoted to the arms of the U frame and adapted to grip the shore member, load lifting means supported by the U frame, and means provided on the frame to hold the pivoting plates in substantially vertical position when the U frame is in substantially horizontal position.

LAWRENCE S. HOLMBOE.