US3601978A

US3601978A - Shortening claw

Info

Publication number: US3601978A
Application number: US860254A
Authority: US
Inventors: Werner Helmut Rieger
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-09-27
Filing date: 1969-09-23
Publication date: 1971-08-31
Anticipated expiration: 1988-08-31
Also published as: BE738686A; CH513348A; DE1775813B1; NL6914663A; FR2018995A1; AT288793B; NL140605B; NO125744B

Abstract

A double prong chain shortening claw having two hooks forming a pocket or pockets to receive the link of a chain, at least one of the pockets having an elastic insert thereon.

Description

United States Patent Inventor Werner llelmut Rleger Hans Haselbach, Unterkochen, Wurttemberg, Germany Appl. No. 860,254 Filed Sept. 23, 1969 Patented Aug. 31, 1971 Priority Sept. 27, 1968' Germany P 17 75 813.3

SHORTENING CLAW 8 Claims, 6 Drawing Figs.

US. Cl 59/93, 7 294/82 Int. Cl F16g 17/00 Field of Search 59/93, 86,

[56] References Cited UNITED STATES PATENTS 2,179,564 11/1939 Smith 59/93 2,878,640 3/1959 Johnson 59/93 3,233,933 2/1966 Coski 294/82 3,333,412 8/1967 Rieger 59/93 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby AttorneySmythe & Moore ABSTRACT: A double prong chain shortening claw having two hooks forming a pocket or pockets to receive the link of a chain, at least one of the pockets having an elastic insert thereon.

PATENYEU M3831 i875 sum 1 0r 2 lnven for;

SHORTENING CLAW The present invention refers to a double-tine shortening claw for chains which formed of two hooks connected to each other by a backpiece and the prongs of which, arranged substantially parallel to each other, are connected at least at the ends to the claw body by cross bars and form a pocket to receive and support a chain link arranged substantially perpendicular to the plane of the slot defined by the prongs.

A shortening claw of the above type is already known in which the shape of the pocket must be adapted relatively precisely to the dimensions of the chain links in order to make certain that the chain can be unhooked therefrom only under certain conditions (German Petty Patent 1,929,820 In the case of known claws, if there is not an exact matching to the dimensions of the links of the chain, then there is the danger that when the chain lies loose, the shortening claw may unintentionally become disengaged unless safety stirrups are additionally applied'after insertion of the chain.

The object of the present invention is to provide a shortening claw in which unhooking of the chain is dependably avoided without the use of a lock stirrup, not only in its stretched position but also in the loose position of the chain, and with which lengths of chain having chain links of different size can be shortened.

In accordance with the present invention, this object is achieved in that in the chain of the aforementioned type, the pocket in the region facing the outer sides of the arms of the supported link is provided in each case with at least one elastic insert member, and the opposing insert members form a pair of clamping jaws for the supported link introduced in each case into the pocket.

The shortening claw of the invention combines the advantages of ease of handling and greater assurance against disengagement, even when the length of chain is completely without a load thereon. Since the elastic insert members are capable of compensating for differences in dimensions between chain links hooked in the shortening claw, one claw can be used for more types of chains than was heretofore possible.

This not only means an increase in the economy of manufacture, but also a saving of costs for stocking by the manufacturer and by the customer.

It has been found particularly advantageous if the hooks form windows having a peripheral annular bead which engages in an annular groove of the corresponding insert member. Such a development permits a particularly simple mounting and removal of the elastic insert members. This is advantageous when an insert member is to be replaced. Since the shortening claw is frequently exposed to external wear, it has been found advisable that the outer surfaces of the insert member do not protrude beyond the outer surfaces of the shortening claw.

One solution, in which the insert members are protected particularly against wear from the outside, consists in having the hooks form a pot-shaped receiving chamber for the insert pieces, which is closed off entirely or partially on the outside of the shortening claw.

Two embodiments of the shortening claw of the invention will be described in further detail below with reference to the accompanying drawing.

In the drawings:

FIG. 1 is a front view of a first form of shortening claw of the invention with a partial section taken along the line l-l in FIG. 2;

FIG. 2 is a cross section seen in the direction of the longitudinal axis of the shortening claw of FIG. 1;

FIG. 3 is a section along the line III-III of FIG. 2;

FIG. 4 is a section corresponding to FIG. 3 through a modified form of a shortening claw; and

FIGS. 5 and 6 are perspective views showing two modified elastic insert members for shortening claws made in accordance with the invention.

In FIGS. l to 3, 11 and 12 are two hooks connected with each other by a backpiece 113, the prongs M, 15 of which are connected at their ends with the claw body by crosspieces l6, 17. Through the

boreholes

18, 19 of the claw body there can be introduced a bolt (not shown) by means of which the shortening claw can be hung up in a manner of a link.

The hooks ll, 12 and the backpiece 13 form a pocket to receive and support a chain link 21, arranged substantially perpendicular to the plane of the slot 20, of a length of chain which is to be shortened.

The pocket is aligned in the region of the outer sides of the

arms

22, 23 of the supported link 21 by

elastic insert pieces

24, 25, the distance between which is about 10 percent less than the outside width of the chain link Zl which normally corresponds to 3.35 to 3.4 times the value of the nominal thickness of the chain link.

The

insert members

24, 25 have a circumferential groove into which an annular head of the opening formed by the hooks engages so as to lock it in its proper position. As can be noted from FIGS. 1 and 2, the outer surfaces of the insert members do not protrude beyond the outer surfaces of the shortening claw so that they are substantially protected against wear.

The embodiment of FIG. 4 corresponds in its basic concept to the embodiment of FIGS. 1 to 3. In the second embodiment, insert

members

26, 27 are, however, arranged in

potshaped receiving chambers

28, 29, which have

small boreholes

30, 31 in the region of their bottom extending to the outside which serve to facilitate the removal of the insert members by permitting the insertion of an ejection tool.

In the case of both shortening claws shown, the insert members are deformed elastically upon the introduction of the chain link 21 and bringing into action elastic holding forces which hold the chain link fast in the claw, even under unfavorable conditions. It is self-evident that in principle, also in the case of the shortening claw of the invention, the length of the prongs l4, 15 which extends from the lower edge of the claw to the prong tip must be sufiiciently large to provide assurance that the chain to be hung on the shortening claw can only be taken out when the link which follows the link 21 held therein is bent sharply out of the direction of pull of the stretched chain.

FIG. 5 shows in perspective an insert member 32 having a central bore 33. This bore serves to increase the flexibility of the insert piece in the case of materials which are intrinsically of only slight softness, such as plastics which are insensitive to oil, cold and heat.

The insert member 34 of FIG. 6 is grooved on the clamping surface 35. The grooving exerts a favorable effect insofar as it keeps low the differences between the clamping forces in case of dry and wet friction.

Numerous modifications are possible without going beyond the scope of the invention. Thus, it is sufficient, for instance, to use merely one elastic insert piece. Such an embodiment will also make possible the clamping fast of the attached chain link. It would be inferior, to be sure, to a shortening claw having two insert members since it could be used only for a smaller range of chain sizes.

What I claim is:

l. A two-prong shortening claw for chains, said claw being formed of two hooks connected with each other by a backpiece, the prongs of said hooks being arranged substantially parallel to each other, the hooks being connected at least adjacent their ends by crosspieces to the claw body, and forming a pocket to receive and support a chain link arranged substantially perpendicular to the plane of a slot defined by the prongs, the pocket being provided in a region facing the outer sides of a supported chain link with at least one elastic insert member to form a clamping jaw for a supported link carried in the pocket.

2. A shortening claw according to claim 1 wherein there is a pair of elastic insert members.

6. A shortening claw according to claim 1 wherein the insert member has a borehole arranged substantially centrally so as to increase its flexibility.

7. A shortening claw according to claim 1 wherein the surfaces of the insert members facing the inside of the pocket are provided with a grooving.

8. A shortening claw according to claim 2 wherein the,

distance between the insert members is approximately 10 percent less than the outside of the chain links.

Claims

1. A two-prong shortening claw for chains, said claw being formed of two hooks connected with each other by a backpiece, the prongs of said hooks being arranged substantiaLly parallel to each other, the hooks being connected at least adjacent their ends by crosspieces to the claw body, and forming a pocket to receive and support a chain link arranged substantially perpendicular to the plane of a slot defined by the prongs, the pocket being provided in a region facing the outer sides of a supported chain link with at least one elastic insert member to form a clamping jaw for a supported link carried in the pocket.

3. A shortening claw according to claim 2 wherein the hooks form windows with a circumferential annular bead which engages in an annular groove of the corresponding insert member.

4. A shortening claw according to claim 3 wherein the outer surfaces of the insert members do not protrude beyond the outer surfaces of the shortening claw.

5. A shortening claw according to claim 2 wherein the hooks have a pot-shaped receiving chamber for the insert members, which chamber is closed off at least partially on the outer side of the shortening claw.

8. A shortening claw according to claim 2 wherein the distance between the insert members is approximately 10 percent less than the outside of the chain links.