Machine element or mechanism – Control lever and linkage systems – Elements
Patent
1989-03-22
1991-10-01
Pellegrino, Stephen C.
Machine element or mechanism
Control lever and linkage systems
Elements
222326, 606 93, 606 92, 30251, 81415, A61F 246, B26B 1326
Patent
active
050522434
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a hand power tool mechanism having a stationary handle, and a drive lever connected to said stationary handle by a joint. More particularly the invention relates to a bone cement caulking gun.
BACKGROUND OF THE INVENTION
Bone cement is used for the anchoring of prosthetic replacements in human bones. It is prepared by mixing a powder component (mainly consisting of polymethylmethacrylate beads and a polymerization catalyst) with a liquid component (mainly consisting of methylmethacrylate monomer) and is applied to the site of implantation by a caulking gun which is used to expel the bone cement mixture in a state of relatively high viscosity. For this purpose the mixed bone cement is filled into a syringe and is extruded by a piston. The power for driving the piston is produced by the action of the hand through a drive mechanism of the friction or ratchet type. In conventional bone cement caulking guns the handles are arranged in a simple kinematic pair, i.e., a pair of pivoted, relatively movable handles in which the position of the strongest fingers is unfavorable for delivering power to the piston.
SUMMARY OF THE INVENTION
The invention is intended to remedy these drawbacks. It solves the problem of how to design a hand power tool with favorable conditions for delivering hand power to the advance mechanism of the tool, in particular a bone cement caulking gun. The invention is equally useful for other hand powered tools, like scissors, pliers or guns for delivering silicone rubber.
The advantages offered by the invention are mainly the better utilisation of hand power.
In a preferred embodiment the four joints of a four-bar linkage mechanism are arranged in such a way that an optimal force/travel ratio for the fingers of the hand results. In particular the two lines connecting the proximal with the distal joints preferably intersect at a point distally to the mechanism from the little finger, preferably at 0.5 to 2.5 lengths of the linkage closure bar.
In a further preferred embodiment of the hand power tool mechanism according to the invention the kinematic joints are replaced by flexible joints, preferably made of elastomer allowing a simpler construction and avoiding cleaning problems especially for surgical applications.
The hand power tool mechanism according to the invention can be used e.g. for a bone cement or silicone rubber caulking gun, for scissors or pliers. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. For the better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which are illustrated and described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a sectional view of a conventional bone cement caulking gun.
FIG. 2 is a perspective view of a conventional scissors.
FIG. 3 is a four bar linkage caulking gun according to the invention.
FIG. 4 is a sectional view of a four bar linkage scissors according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 represents a conventional bone cement caulking gun with a stationary handle 1 connected to the body 2 and a movable handle 3 pivotally connected to the stationary handle 1 by means of the pivot point 4. Movement of the handle 3 as indicated by arrow 5a results in the movement indicated by arrow 6 of the bar 7 which advances rod 9 via pusher 8. Piston plate 10 advances forwardly as indicated by arrow 36 for each squeeze of the handles 1,3 extruding material 11 from the syringe 12 through a nozzle 13. On the return stroke, the direction of which is indicated by arrow 5b, the rod 9 is prevented from retracting by a brake 14. Position of the hand on the handles 1,3 is indicated by circles 21 for the palm, 22 for the index, 23 for the middle finger, 24 for the ring-finger and 25 for
REFERENCES:
patent: 1238733 (1917-09-01), Arden
patent: 2442424 (1948-06-01), McGary et al.
patent: 3572192 (1971-03-01), Juras
patent: 4368577 (1983-01-01), Babb
A. A. Amis, "Variation of Finger Forces in Maximal Isometric Grasp Tests on a Range of Cylinder Diameters", J. Biomed. Eng., 1987, vol. 9, Oct., pp. 313-320.
Dawson Glenn K.
Farley Walter C.
Laboratorium fur experimentelle Chirurgie
Pellegrino Stephen C.
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