diff --git a/js/uhr.js b/js/uhr.js
index 4ede129..aa823be 100644
--- a/js/uhr.js
+++ b/js/uhr.js
@@ -58,7 +58,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
     var start = function start() {
         if (!isOn(this)) {
             var uhr = this;
-            this._timer = window.setInterval(function uhrTimer() {
+            this.timer = window.setInterval(function uhrTimer() {
                 uhr.options.time = new Date();
                 update(uhr);
             }, 1000);
@@ -68,8 +68,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
     };
     var stop = function stop() {
         if (isOn(this)) {
-            window.clearInterval(this._timer);
-            this._timer = null;
+            window.clearInterval(this.timer);
+            this.timer = null;
             update(this);
             setCookie(this, 'uhr-status', 'off');
         }
@@ -107,8 +107,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
         if (time === null) {
             this.options.time = new Date();
         } else {
-            if (this._timer !== null) {
-                window.clearInterval(this._timer);
+            if (this.timer !== null) {
+                window.clearInterval(this.timer);
             }
             this.options.time = time;
         }
@@ -118,6 +118,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
     // private interface methods
     var create = function create() {
         this._id = uhrGlobals.id++;
+        this.timer = null;
+        this._currentMinute = -1;
         var userTime = this.options.time;
         if (this.options.time === undefined) {
             this.options.time = new Date();
@@ -265,7 +267,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
     // business logic
     var isOn = function isOn(uhr) {
-        return uhr._timer !== null;
+        return uhr.timer !== null;
     };
     var update = function update(uhr) {
         if (isOn(uhr)) {
@@ -349,11 +351,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
         "theme": setTheme,
         "time": setTime,
         // constructor method
-        "_create": create,
-        // private variables
-        "_id": -1,
-        "_timer": null,
-        "_currentMinute": -1
+        "_create": create
     });
     $.fritteli.uhr.register = uhrGlobals.registerLanguage;
 	/**