US2489905A

US2489905A - Cut ring expander

Info

Publication number: US2489905A
Application number: US697532A
Authority: US
Inventors: Kuert Fritz
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1945-12-18
Filing date: 1946-09-17
Publication date: 1949-11-29
Anticipated expiration: 1966-11-29

Description

NOV. 29, 1949 KUERT 2,489,905

CUT RING EXPANDER Filed Sept. 17, 1946 QJMIKLQMM A TTORNE Y5 Patented Nov. 29, 1949 CUT RING EXPANDER Fritz Kuert, Winterthur, Switzerland, assignor to Sulzer Freres, Societe Anonyme, Winterthur,

Switzerland Application September 17, 1946, Serial N 0. 697,532 In Switzerland December 18, 1945 6 Claims.

This invention relates to a device for expanding cut rings, in particular piston rings, and is characterised by an expanding tongs and two gripping arms, each of the latter having a gripping piece to hold one end of the ring and each being connected by two links to an arm of the expanding tongs.

It is preferable to construct the device in such a way that each arm of the expanding tongs, together with the gripper arm linked to it and the links, forms a parallelogram. One of the links to each gripper arm and the two arms of the expanding tongs can have one common pivot point. The arms of the expanding tongs may however also be linked to a connecting body at separate places but in positive running engagement with each other.

The invention is further explained below through two simplified embodiments of it shown in the drawing. Fig. 1 shows an expander in which each arm of the expanding tongs, together with the gripper arm linked to it and the links, forms a parallelogram. Fig. 2 illustrates an expander in which the arms of the expanding tongs are linked at separate spots to a connecting body 55 but are in positive running engagement with each other. 7

The expanding device shown in Fig. 1 has a two-armed expanding tongs, the arms l of which form lever arms, and two gripper arms 2. Each of the gripper arms 2 is fitted at one end with an elongated gripper 3 which extends lengthwise therefrom for holding the end of the cut ring 4. Each gripper arm 2 is linked at two points 5 and 6 to two spaced links 1 and 8 of substantially equal length, whilst these links in their turn are pivotably connected at the points 9 and ID to a lever arm of the expanding tongs. Except for the pivotal connections 5 and 6, and 9 and Ill, the links 1 and 3 are unrestrained. The distances between points 5 and 6 are the same as the distances between points 9 and I0. Each lever arm I of the expanding tongs consequently forms with the linked-on gripper arm 2 and the respective links 1 and 8 a parallelogram whose angle may be altered as desired when the gripper 3 is not in use. The distance between the two grippers 3 may in this way be suited to the distance between the two ends of the ring. The front links I and the two lever arms I of the expanding tongs are linked together at the common pivot point 9. The tongs are opened out by means of a spindle ll provided with left hand and right hand screw threads and running in nuts l2 and I3 pivotably connected to the lever arms of the tongs.

2 r When using the expanding device, with the lever arms I of the tongs approached to each other, each of the grippers 3 is brought over an end of the ring 4. By causing the lever arms I of the tongs to spread apart by means of the spindle II, the angular position of the gripper arms 2 with respect to each other is changed. In consequence of the possibility of altering the angles of the parallelogram, the distance between the grippers remains unchanged; it is always equal to the distance between the ends of the rings until the fingers l4 and I5 come both to rest on the surfaces of the ring ends. Until the fingers come into that position, no forces are exerted by the tongs on the ring. As shown in the drawings, the finger l4 engages an inner-face portion of the ring while'the finger l5 engages the outer periphery of the ring at a distance spaced from its adjacent cut end.

If the expanding tongs is opened further, from the moment when the fingers come to lie on the ends of the ring, each of the grippers exerts on the ring end held by it two equal but opposite couples. Single forces are not exerted by the grippers on the ends of the ring, since the distance between the two gripper arms can at any time suit itself to the distance between the ends of the rings without any resistance. In consequence of the action of the couples, the ring 4 will be opened against its elastic forces. Then each cross-section of the ring 4 will be stressed only by a pure bending moment, but not by any lateral pull or pressure. It is thus possible, in the case of piston rings (or in the case of other rings which have for instance to be inserted into grooves or removed from them), to prevent over-stressing because of the action of unsuitable forces when opening them.

In the device illustrated in Fig. 2, the two lever arms I of the tongs are not linked together at one common pivot point, but separately to two points l6 of a connectingpiece I1 and kept in positive running engagement with each other through meshing gear segments. The gripper arms 2 are in linked connection with the points Ill and I8 of the lever arms I of the tongs through two links 1 and 8 of different lengths.

The lever arms I of the expanding tongs are opened by a pressing tongs consisting of two arms l9 and 20 pivoted at 24 and held open by spring 24 which are linked at the points 2| and 22 to the lever arms of the expanding tongs. By pressing the two handles l9 and 20 of the pressing tongs together the lever arms of the expanding tongs are opened and a ring is thereby expanded.

According to the dimension chosen for the distance between the two pivot points IS on the connecting piece H, the length of the links 1 and 8 and the distances between the pivot points 5, 6, l and I8, a single force corresponding to requirements can be exerted also on the ring elements, and this may lead to a more -favourable distribution of the stresses in the case of special rings.

I claim:

1. An expanding tong device for insertion into an opening and exerting outward pressure on opposite sides thereof including a :pair of lever arms, means connecting the lever arm's for;pivota'l motion with respect to one another, a pair of elongated pressure members, one .pressure member extending in the same general direction as one of the lever arms and the other pressure member extending in the same general direction as the other lever arm, a pair of separate links pivotally nonnecting each pressure member to its correspondih'g leVerarm, eachl-ink being freelyspivoted at 'one end to-"apressure nrember and atits other end to the-corresponding lever arm, corresponding *ends of the pressure members being {positionable adjacent one another, andmeansa'tsaid corresponding "end of each lpr-essure member -for engaging "the corresponding side of the opening into "which it is inserted :to cooperatively secure fithat-end 6f thatzpressure :m'emb'er tOsaidcOrr'es'iiondingside'of the operiing.

2. expanding tdng device as llefined in 'ciaiih l in =iivliich a parallelogram is formed by each -le'ver arm together with :its corresponding :pre's'sufe member "and '"the links connectin'g them. *3. :"An expanding t'ohg device as defined in cl'aim 1 in'wliichpneoftlie links of each pair "and the '-:two -Ieverar-ms are connected at "a common point. 4. An expanding tong device "as defiired in Fcraim 1 in which the pivotal connection between the Il/e' arm's "Comprises "a 1001151 and separate s'pacedpiv" sfor'ea'oh lever arm and which *l-ild'e's iii" 'h'ga'g-ihg portions onth'e level arms ro 'con oi movementoftnem.

5. A out ring expander co'mprising a p'air of Te'if'r arfii's, meansconnecting the lei/e1 alfmsTGr Di-Vdtal indtfdn with respect to Oh'e another, "a

painofeiohgated gripper members, one gri per member extending in the same general direction as one of the lever arms and the other gripper member extending in the same general direction as the other lever arm, a pair of otherwise unrestrained separate links pivotally connecting each gripper member to its corresponding lever arm, each link being ,pivoted at :one end to a gripper mem'ber and at its other "end to the corresponding lever arm, corresponding ends of the gripper members being positionable adjacent one another, and means at said corresponding ends of each 'gripp'ef'member for securing that end of that grippermember to anend of a cut ring.

6. A cut ring expander comprising a pair of lever arms, means "connecting the'lever arms for ,pivotal motion with respect to one another, a .pair of elongated gripper members, one gripper member extending in the same general direction as one of the lever arms and the other gripper member extending in the same general direction as the other lever arm, aipair of separate links pivotally connecting each gripper member to its corresponding lever arm, each link being freely pivoted atone 'end "toa sgrip'per member and at its oth'er erid to'the oorresponding lever arm, each -01 "saidigripp'ermembers having at one end thereof a finger extending therefrom in a, direction generally longitudinally of the gripper :member, the distal -end of 'ea'ch fing er having an overhanging 'p'rfition'lext'ending therefrom to engage an inner face -portion :bf a cut ring adjacent one end there'o said end Cof ea'ch :gripper member also having 'a portion "spaced irom the finger thereof in adirectiongeneraliy transversely of the gripper nfember :to bear on the outer periphery of "the ring at a distance f-rom su'ch end thereof FRITZ KUERT.

CITED 'Tli'e "renewing rbferences are of record in the file of this patent:

STATES PATENTS Number Name Date -1,466;659 'Kabanuck Sept. 4, 1923 1,718,121 Denton June 18, 1929 1,760,980 Foreman June 3, 1930 133081064 :Pe'a'rinan 'et a1. June 2, 1931